datavorous/entrance-exam-dataset huggingface dataset:
Which of the following is used for the conversion of 1-methylcyclopentene to

Options:
A BD 3 THF followed by CH 3 COOH
B BH 3 THF followed by CH 3 COOD
C BD 3 THF followed by CH 3 COOD
D BH 3 THF followed by CH 3 COOH

The correct answer is:
BH 3 THF followed by CH 3 COOD

Solution:
The following reaction proceeds through Anti-Markownikoff's addition. Boron gets attached to the more substituted Carbon and the acidic Deuterium from CH 3 COOD gets attached to the less substituted Carbon.

Topic: Chemistry, Hydrocarbons, JEE Main
Which of the following is used for the preparation of colloids ?

Options:
A Ostwald process
B Van Arkel Method
C Bredig's Arc Method
D Mond Process

The correct answer is:
Bredig's Arc Method

Solution:
Bredig’s Arc Method is used for preparation of colloidal sol’s of less reactive metal like Au, Ag, Pt.

Ostwald process is used for preparation of nitric acid.

Van Arkel method is used for refining Zirconium or Titanium.

The Mond process is a method for refining nickel. The nickel oxide and impurities react with the hydrogen gas to form an impure solid nickel.

Topic: Chemistry, Surface Chemistry, JEE Main, JEE Main 2020 (02 Sep Shift 1)
Which of the following is used in gene cloning?

Options:
A Nucleoids
B Lomasomes
C Mesosomes
D Plasmids

The correct answer is:
Plasmids

Solution:
Plasmids are extrachromosomal genetic elements (DNA) found in bacterial cells. These can exist and replicate independently of the bacterial chromosome. Now-a-days, plasmids are widely used as vectors to produce recombinant DNA for gene cloning.

Topic: Biology, Biotechnology - Principles and Processes, NEET, NEET 2010 (Mains)
Which of the following is used in optical fibres ?

Options:
A
total internal reflection

B
scattering

C
diffraction

D
refraction

The correct answer is:
total internal reflection

Solution:
No Solution Available

Topic: Physics, Ray Optics, JEE Main, JEE Main 2002
Which of the following is used in the preparation of chlorine?

Options:
A Only $\mathrm{MnO}_{2}$
B $\quad$ Only $\mathrm{KMnO}_{4}$
C Both $\mathrm{MnO}_{2}$ and $\mathrm{KMnO}_{4}$
D Either $\mathrm{MnO}_{2}$, or $\mathrm{KMnO}_{4}$

The correct answer is:
Both $\mathrm{MnO}_{2}$ and $\mathrm{KMnO}_{4}$

Solution:
Both $\mathrm{MnO}_{2}$ and $\mathrm{KMnO}_{4}$ used for the preparation of chlorine by the action of conc. $\mathrm{HCl}$
$$
\begin{array}{l}
\mathrm{MnO}_{2}+4 \mathrm{HCl} \rightarrow \mathrm{MnCl}_{2}+2 \mathrm{H}_{2} \mathrm{O}+\mathrm{Cl}_{2} \\
2 \mathrm{KMnO}_{4}+16 \mathrm{HCl} \rightarrow 2 \mathrm{KCl}+2 \mathrm{MnCl}_{2} \\
+8 \mathrm{H}_{2} \mathrm{O}+5 \mathrm{Cl}_{2}
\end{array}
$$
Chlorine is not obtained by dil. $\mathrm{HCl}$
$$
\mathrm{Ag}_{2} \mathrm{~S}_{2} \mathrm{O}_{3}+\mathrm{H}_{2} \mathrm{O} \rightarrow \mathrm{Ag}_{2} \mathrm{~S}+\mathrm{H}_{2} \mathrm{SO}_{4}
$$

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main
Which of the following is used in the treatment of thyroid cancer?

Options:
A $\mathrm{I}_{131}$
B $U_{238}$
C $\mathrm{Ra}_{224}$
D $\mathrm{C}_{14}$

The correct answer is:
$\mathrm{I}_{131}$

Solution:
External radiation therapy and radioactive iodine therapy are used to treat thyroid cancer.
Related Theory
Radiation therapy may be given after surgery to kill any thyroid cancer cells that were not removed. Follicular and papillary thyroid cancers are sometimes treated with radioactive iodine (RAI) therapy. RAI is taken by mouth and collects in any remaining thyroid tissue, including thyroid cancer cells that have spread to other places in the body. Since only thyroid tissue takes up iodine, the RAI destroys thyroid tissue and thyroid cancer cells without harming other tissue.

Topic: Biology, Human Health and Diseases, NEET, NEET 2002
Which of the following is used to prepare a medicine, which is used in making an important explosive, RDX ?

Options:
A Acetaldehyde
B Acetone
C Formaldehyde
D None of these

The correct answer is:
Formaldehyde

Solution:
Formaldehyde, on treating with ammonia, gives urotropine which is used as medicine and in making an important explosive, cyclonite or RDX
6 HCHO + 4 NH 3 â¶ CH 2 6 N 4 + 6 H 2 O hexamethylene tetraamine (urotropine)

Topic: Chemistry, Aldehydes and Ketones, JEE Main
Which of the following is used to prepare the inner lining of a blast furnance?

Options:
A Graphite bricks
B Silica bricks
C Fire clay bricks
D basic bricks

The correct answer is:
Fire clay bricks

Solution:
Fire clay bricks is used to prepare the inner lining of a blast furnance. It is highly refractory in nature and does not melt, even at huge temperature. Its main components are silica and alumina.

Topic: Chemistry, General Principles and Processes of Isolation of Metals, COMEDK, COMEDK 2022
Which of the following is valid at absolute zero

Options:
A Kinetic energy of the gas becomes zero but the molecular motion does not become zero
B Kinetic energy of the gas becomes zero and molecular motion also becomes zero
C Kinetic energy of the gas decreases but does not become zero
D None of the above

The correct answer is:
Kinetic energy of the gas decreases but does not become zero

Solution:
Kinetic energy of the gas decreases but does not become zero

Topic: Chemistry, States of Matter, JEE Main
Which of the following is wrong statement?

Options:
A Ozone is violet-black in solid state
B Ozone is diamagnetic gas
C ONCl and ONO- are isoelectronic
D O3 molecule is bent

The correct answer is:
ONCl and ONO- are isoelectronic

Solution:
Ozone in solid state is violet-black solid.
All paired electrons, so it is diamagnetic as per Lewis structure.
ONCl – no. of electrons = 32
ONO– – no. of electrons = 24
They are not isoelectronic.
O3 has bent structure with Bond angle 116.8o .

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main, JEE Main 2013 (07 Apr)
Which of the following is wrongly matched?

Options:
A IUI - semen collected from husband or donor is artificially introduced either into the vagina or into the uterus
B GIFT - transfer of embryos with more than 8 blastomeres into the Fallopian tube
C ICSI - sperm directly injected into the ovum
D ZIFT - transfer of embryos with upto 8 blastomeres into the Fallopian tube

The correct answer is:
GIFT - transfer of embryos with more than 8 blastomeres into the Fallopian tube

Solution:
GIFT or gamete intra-fallopian transfer:
â This technique is employed for the females with prolonged sterility but having at least one patent fallopian tube.
â This is useful where fimbriae fail to capture the ovum or females having sperm antibodies in their cervical secretions.
â This technique involves the transfer of washed sperms and harvested ova to the ampulla of the fallopian tube with the help of a laparoscope.
â

Topic: Biology, Reproductive Health, NEET
Which of the following is/are character/s of racemose inflorescence?

(i) Basal flower are older while the apical flowers are younger.
(ii) Flower open from periphery to centre.
(iii) Floral axis shows continuous growth

Options:
A Only i and iii
B Only ii
C Only iii
D i, ii and iii

The correct answer is:
i, ii and iii

Solution:
The arrangement of flowers on the floral axis is termed as inflorescence. Depending on whether the apex gets developed into a flower or continues to grow, two major types of inflorescences are defined - racemose and cymose. In racemose type of inflorescences the main axis continues to grow, the flowers are borne laterally in an acropetal Succession.

Topic: Biology, Morphology of Flowering Plants, NEET
Which of the following is/are correct for the first order reaction? (a is initial concentration of reactant, x is concentration of the reactant reacted and t is time)

Options:
A I and II only
B II and III only
C I, II and III only
D I and III only

The correct answer is:
I, II and III only

Solution:
I log (a - x) (where a-x is the remaining concentration), decreases with the passage of time.
II kt=2.303log⁡aa-x
III For first order t12 is independent of a

Topic: Chemistry, Chemical Kinetics, JEE Main
Which of the following is/are correct for the first order reaction?

Options:
A I, II
B II, III
C I, II III
D I, III

The correct answer is:
I, II

Solution:
I. log (a â x), where (a â x) is remaining concentration, decreases with passage of time.

logaâx=log aâkt2.303

y=log aâk2.3030x

slope=âve
II. k=2.303tlog10â¡aa-x
log aa-x=k2.303Ãt=y=k2.303x
y=mÃx
Plot of logâ¡aa-x against 't' gives straight line through origin.
III. t1/2=0.693k; Half-life of first order reaction does not depend on initial concentration. Thus, graph of t1/2 against 'a' gives horizontal straight line.

Topic: Chemistry, Chemical Kinetics, JEE Main
Which of the following is/are counter example(s) of the statement \( x^{2}-7 x+10>0 \), for all real \( x ? \)
(i) \( 2 \) (ii) \( 3 \) (iii) \( 4 \) (iv) \( 5 \)

Options:
A Only (i) and (iv)
B Only (ii) and (iii)
C (i), (ii), (iii) and (iv)
D None of these

The correct answer is:
(i), (ii), (iii) and (iv)

Solution:
We have,

x2-7x+10>0

⇒x-2x-5>0
⇒x∈-∞,2∪5,∞
Clearly, x=2, 3, 4, 5 does not satisfy

Topic: Mathematics, Mathematical Reasoning, JEE Main
Which of the following IUDs make the uterus unsuitable for implantation and the cervix hostile to the sperms?

Options:
A Lippe's loop
B Copper releasing IUDs
C Hormone releasing IUDs
D Multiload 375 IUDs

The correct answer is:
Hormone releasing IUDs

Solution:
Hormone releasing IUD have progesterone that effects on endometrium to the foreign body reaction. The progesterone IUD mainly acts by inhibition of implantation, sperm-capacitation and their survival.

Topic: Biology, Reproductive Health, NEET
Which of the following laws of Physics is valid across all domains of nature?

Options:
A Newton's law of motion
B Conservation of momentum
C Conservation of energy
D All of the above

The correct answer is:
Conservation of energy

Solution:
Law of conservation of energy is valid across all domains of nature. In the universe, all kinds of violent phenomenon occur all the time. Yet the total energy of the universe is remains conserved.

Topic: Physics, Laws of Motion, COMEDK, COMEDK 2020
Which of the following lewis acidity order of \( \mathrm{BX}_{3} \) is correct?

Options:
A \( \mathrm{BF}_{3} < \mathrm{BCl}_{3} < \mathrm{BBr}_{3} < \mathrm{BI}_{3} \)
B \( \mathrm{BF}_{3}>\mathrm{BCl}_{3}>\mathrm{BBr}_{3}>\mathrm{BI}_{3} \)
C \( \mathrm{BCl}_{3} < \mathrm{BBr}_{3} < \mathrm{BI}_{3} < \mathrm{BF}_{3} \)
D \( \mathrm{BF}_{3} < \mathrm{BI}_{3} < \mathrm{BBr}_{3} < \mathrm{BCl}_{3} \)

The correct answer is:
\( \mathrm{BF}_{3} < \mathrm{BCl}_{3} < \mathrm{BBr}_{3} < \mathrm{BI}_{3} \)

Solution:
A Lewis acid is a chemical species that contains an empty orbital which is capable of accepting an electron pair from a Lewis base to form a Lewis adduct.

This can be explained on the basis of tendency of halogen atom to back donate its lone pair of electrons to the empty p-orbital of boron atom through pπ-pπbonding. As this tenedency is higher in case of F (due to identical size of 2p- orbitals of boron and fluorine) the electron deficiency of boron decreases and thus BF3 behaves as weakest Lewis acid. As the size of halogen atom increases from Cl to I, the tendency for back donation decreases and consequently the electron deficiency of boron increases and Lewis acid character increases accordingly from BF3 to BI3.

BF3<BCl3<BBr3<BI3

Topic: Chemistry, p Block Elements (Group 13 & 14), JEE Main
Which of the following ligands forms a chelate

Options:
A Acetate
B Oxalate
C Cyanide
D Ammonia

The correct answer is:
Oxalate

Solution:
As it makes use of its two atoms to form two co-ordinate covalent bonds with the central metal ion.

Topic: Chemistry, Coordination Compounds, JEE Main
Which of the following ligands is expected to bidentate

Options:
A $\mathrm{Br}$
B $\mathrm{C}_2 \mathrm{O}_4^{2-}$
C $\mathrm{CH}_3 \mathrm{NH}_2$
D $\mathrm{CH}_3 \mathrm{C} \equiv \mathrm{N}$

The correct answer is:
$\mathrm{C}_2 \mathrm{O}_4^{2-}$

Solution:
$\mathrm{C}_2 \mathrm{O}_4^{2-}$ has two donor O atoms and hence is a bidentate ligand.

Topic: Chemistry, Coordination Compounds, JEE Main
Which of the following line is a diameter of the circle $x^2+y^2-6 x-8 y-9=0$

Options:
A $3 x-4 y=0$
B $4 x-3 y=9$
C $x+y=7$
D $x-y=1$

The correct answer is:
$x+y=7$

Solution:
Centre $(3,4)$ is satisfying only $x+y=7$.

Topic: Mathematics, Circle, JEE Main
Which of the following lines correctly show the temperature dependence of equilibrium constant K, for an exothermic reaction?

Options:
A A & D
B A & B
C B & C
D C & D

The correct answer is:
A & B

Solution:
The Arrhenius equation in Logarithmic form:

In K=-∆HRT+ln A

On comparing with y=mx+c, m=-∆HR and c=ln A.

For an exothermic reaction, the value of ∆H<0, slope will be positive and the intercept can be either positive or negative.

Topic: Chemistry, Chemical Equilibrium, JEE Main, JEE Main 2018 (08 Apr)
Which of the following lines correctly show the temperature dependence of equilibrium constant K, for an exothermic reaction?

Options:
A A and D
B A and B
C B and C
D C and D

The correct answer is:
A and B

Solution:
ÎGo=-RT ln K
ÎHo-TÎSo=-RT ln K
− ΔH o RT + ΔS o R =lnK
Therefore lnâ¡ K vs 1T graph will be a straight line with slope equal to -ÎHoR . Since reaction is exothermic, therefore ÎHo itself will be negative resulting in positive slope.

Topic: Chemistry, Chemical Equilibrium, JEE Main
Which of the following lines is concurrent with the lines $3 x+4 y+6=0$ and $6 x+5 y+9=0$

Options:
A $2 x+3 y+5=0$
B $3 x+3 y+5=0$
C $7 x+9 y+3=0$
D None of these

The correct answer is:
$3 x+3 y+5=0$

Solution:
Check by options.
From option (a),
$\left|\begin{array}{lll}
3 & 4 & 6 \\
6 & 5 & 9 \\
2 & 3 & 5
\end{array}\right|=3(25-27)-4(12)+6(8) \neq 0$
From option (b),
$\left|\begin{array}{lll}
3 & 4 & 6 \\
6 & 5 & 9 \\
3 & 3 & 5
\end{array}\right|=3(25-27)-4(3)+6(3)=0$

Topic: Mathematics, Straight Lines, JEE Main
Which of the following liquid pairs shows a positive deviation from Raoult's law?

Options:
A
Water - hydrochloric acid

B
Acetone - chloroform

C
Water - nitric acid

D
Benzene - methanol

The correct answer is:
Benzene - methanol

Solution:
Benzene in methanol breaks the $\mathrm{H}$ - bonding of the alcohol making its boiling point decrease \& there by its vapour pressure increases leading two +ve deviation.

Topic: Chemistry, Solutions, JEE Main, JEE Main 2004
Which of the following liquid pairs shows a positive deviation from Raoult's law

Options:
A Water-nitric acid
B Benzene-methanol
C Water-hydrochloric acid
D Acetone-chloroform

The correct answer is:
Benzene-methanol

Solution:
In solution showing positive type of deviation the partial pressure of each component of solution is greater than the vapour pressure as expected according to Raoult's law.
In solution of methanol & benzene methanol molecules are held together due to hydrogen bonding as shown below.
On adding benzene, the benzene molecules get in between the molecule of methanol thus breaking the hydrogen bonds. As the resulting solution has weak intermolecular attraction, the escaping tendency of alcohol & benzene molecule from the solution increases. Consequently the vapour pressure of the solution is greater than the vapour pressure as expected from Raoult's law.

Topic: Chemistry, Solutions, JEE Main
Which of the following locations acts as the reservoir for nitrogen cycle?

Options:
A Atmosphere
B Sedimentary bedrock
C Soil
D Fossilised plant and animal remains

The correct answer is:
Atmosphere

Solution:
The reservoir is the main storehouse of the nutrient on the earth from which the nutrient is transferred to the cycling pool. That is the place from which cycling of nutrients occurs. For nitrogen, reservoir and cycling pools both are the atmosphere, hence it is a gaseous cycle.

Topic: Biology, Ecosystem, NEET
Which of the following logic gate is an universal gate

Options:
A OR
B NOT
C AND
D NOR

The correct answer is:
NOR

Solution:
'NOR' gates are considered as universal gates, because all the gates like AND, OR, NOT can be obtained by using only NOR gates.

Topic: Physics, Semiconductors, JEE Main
Which of the following logic gate is universal gate

Options:
A
B
C
D

The correct answer is:

Solution:
NAND gate is an universal gate.

Topic: Physics, Semiconductors, JEE Main
Which of the following magnetic materials have small area of hysteresis loop?

Options:
A Saturable magnetic material
B Soft magnetic material
C Hard magnetic material
D Diamagnetic material

The correct answer is:
Soft magnetic material

Solution:
The soft magnetic materials have low value of coercivity and high value of permeability. The area of hysteresis loop of the soft magnetic materials is small, as a result the hysteresis loss in case of soft magnetic materials is less.

Topic: Physics, Magnetic Properties of Matter, JEE Main
Which of the following maintains continuity between the water and lipid phases inside and outside the cells?

Options:
A Cell Wall
B Lecithin
C Cell vacuole
D Cell membrane of woody plants

The correct answer is:
Lecithin

Solution:
The smooth endoplasmic reticulum produces nearly all of the lipids required for the elaboration of new cell membranes, including both phospholipids and cholesterol. The major phospholipid is made up of phosphatidylcholine, also called lecithin. Lecithin maintains continuity between the water and lipid phases inside and outside the cell.

Topic: Biology, Cell - The Unit of Life, NEET
Which of the following matches is correct?

Options:
A Phytopthora → Aseptate mycelium → Basidiomycetes
B Alternania → Sexual reproduction absent → Deuteromycetes
C Mucor → Reproduction by conjugation → Ascomycetes
D Agaricus → Parasitic fungus → Basidiomycetes

The correct answer is:
Alternania → Sexual reproduction absent → Deuteromycetes

Solution:
Phytophthora has aseptate mycelium and is a member of Phycomycetes. In mucor, reproduction occurs by the gametangial copulation and it is a member of Phycomycetes. Agaricus is commonly called as the mushroom is a saprophytic fungus which grows mainly on decaying wood and is a member of basidiomycetes.

Topic: Biology, Biological Classification, NEET
Which of the following matches is not true for the hormone and their functions?

Options:
A Thyroxine: maintenance of water and electrolyte balance
B Cortisol: stimulate the formation of erythrocytes
C Melatonin: influences pigmentation and menstrual cycle
D All of the above are correctly matched.

The correct answer is:
All of the above are correctly matched.

Solution:
Thyroxine: regulate basal metabolic rate, support RBC formation and also maintains water and electrolyte balance. Cortisol hormone stimulates erythropoiesis that is the formation of erythrocytes. MSH influences pigmentation (formation of melanin) and maintains the mentrual cycle.

Topic: Biology, Chemical Coordination and Integration, NEET
Which of the following material is not a semiconductor.

Options:
A Silicon
B Copper oxide
C Germanium
D Graphite

The correct answer is:
Graphite

Solution:
Graphite is conductor

Topic: Chemistry, Classification of Elements and Periodicity in Properties, JEE Main, JEE Main 2024 (06 Apr Shift 1)
Which of the following matrices can NOT be obtained from the matrix -121-1 by a single elementary row operation?

Options:
A 011-1
B 1-1-12
C -12-27
D -12-13

The correct answer is:
-12-27

Solution:
Given A=-121-1

(1) R1→R1+R2

011-1

(2) R1↔R2

1-1-12

(3) Option is not possible

(4) R2→R2+2R1

-12-13

Topic: Mathematics, Matrices, JEE Main
Which of the following matrices can NOT be obtained from the matrix -121-1 by a single elementary row operation?

Options:
A 011-1
B 1-1-12
C -12-27
D -12-13

The correct answer is:
-12-27

Solution:
Given A=-121-1

(1) R1→R1+R2

011-1

(2) R1↔R2

1-1-12

(3) Option is not possible

(4) R2→R2+2R1

-12-13

Topic: Mathematics, Matrices, JEE Main, JEE Main 2022 (29 Jul Shift 2)
Which of the following Maxwell's equations is valid for time varying conditions but not valid for static conditions :

Options:
A $\oint \overrightarrow{\mathrm{B}} \cdot \overrightarrow{\mathrm{dl}}=\mu_0 \mathrm{I}$
B $\oint \overrightarrow{\mathrm{E}} \cdot \overrightarrow{\mathrm{dl}}=0$
C $\oint \overrightarrow{\mathrm{E}} \cdot \overrightarrow{\mathrm{dl}}=-\frac{\partial \phi_{\mathrm{B}}}{\partial \mathrm{t}}$
D $\oint \overrightarrow{\mathrm{D}} \cdot \overrightarrow{\mathrm{dA}}=\mathrm{Q}$

The correct answer is:
$\oint \overrightarrow{\mathrm{E}} \cdot \overrightarrow{\mathrm{dl}}=-\frac{\partial \phi_{\mathrm{B}}}{\partial \mathrm{t}}$

Solution:
For time varying condition Maxwell's equation, $\oint \overrightarrow{\mathrm{E}} \cdot \overrightarrow{\mathrm{dl}}=-\frac{\mathrm{d} \phi_{\mathrm{B}}}{\mathrm{dt}}$

Topic: Physics, Electromagnetic Waves, JEE Main
Which of the following metal carbonate is decomposed on heating

Options:
A $\mathrm{MgCO}_3$
B $\mathrm{Na}_2 \mathrm{CO}_3$
C $\mathrm{K}_2 \mathrm{CO}_3$
D $\mathrm{Rb}_2 \mathrm{CO}_3$

The correct answer is:
$\mathrm{MgCO}_3$

Solution:
$\mathrm{MgCO} 3 \Rightarrow \mathrm{MgO}+\mathrm{CO}_2$
The metal whose oxide is stable, it's carbonate is unstable

Topic: Chemistry, s Block Elements, JEE Main
Which of the following metal ions will form complexes with the same magnetic moment and geometry irrespective of the nature of ligands?

Options:
A \(\mathrm{Ni}^{2+}\)
B \(\mathrm{Fe}^{2+}\)
C \(\mathrm{Cu}^{2+}\)
D \(\mathrm{Co}^{2+}\)

The correct answer is:
\(\mathrm{Cu}^{2+}\)

Solution:
In presence of either strong field or weak field, the number of unpaired electron remains the same in case of \(\mathrm{Cu}^{2+}\) ion.

Topic: Chemistry, Coordination Compounds, AIIMS, AIIMS 2007
Which of the following metal ions will have maximum number of unpaired electrons

Options:
A $\mathrm{Fe}^{+2}$
B $\mathrm{CO}^{+2}$
C $\mathrm{Ni}^{+2}$
D $M n^{+2}$

The correct answer is:
$M n^{+2}$

Solution:
$M n^{+2}$ ion will have five (maximum) unpaired electrons

Topic: Chemistry, Structure of Atom, JEE Main
Which of the following metal is found in green colouring pigment chlorophyll of plants

Options:
A $\mathrm{Fe}$
B $M g$
C $\mathrm{Na}$
D Al

The correct answer is:
$M g$

Solution:
Magnesium (Mg) is present in Chlorophyll.

Topic: Chemistry, s Block Elements, JEE Main
Which of the following metal nitrate produces gaseous product when reacts with KCN solution?

Options:
A Cu(NO3)2
B AgNO3
C Cd(NO3)2
D Pb(NO3)2

The correct answer is:
Cu(NO3)2

Solution:
(A)2Cu(NO 3 ) 2  + 4KCN→ KNO 3 + 2CuCN Redox +(CN) 2 ↑
B AgNO3+KCNâKNO3+AgCNâ (ppt. formation)
C Cd(NO3)2+2KCNâ2KNO3+Pb(CN)2â (ppt formation)
D Pb(NO3)2+2KCNâ2KNO3+Pb(CN)2â (ppt formation)

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main
Which of the following metal pairs on burning in moist air do not give smell of ammonia?
Mg, Ca, K, Li, Na, Al

Options:
A Mg, K
B Ca, Na
C K, Na
D Li, Al

The correct answer is:
K, Na

Solution:
Mg+N2→Mg3N2→moistH2OMgOH2+NH3

Ca+N2→Ca3N2→moistH2OCaOH2+NH3

Li+N2→Li3N→moistH2OLiOH+NH3

K+N2→ no reaction
Na+N2→ no reaction
Hence, Sodium and Potassium do not give smell of ammonia.

Topic: Chemistry, s Block Elements, JEE Main
Which of the following metals can be extracted through alkali leaching technique?

Options:
A Sn
B Pb
C Au
D Cu

The correct answer is:
Sn

Solution:
Leaching is often used if the ore is soluble in some suitable solvent. The ore of tin metal is cassiterite(SnO2). Cassiterite is readily soluble in alkali. The reaction is shown below.

SnO2+2NaOH+2H2O→Na2Sn(OH)6

Topic: Chemistry, General Principles and Processes of Isolation of Metals, JEE Main, JEE Main 2023 (08 Apr Shift 1)
Which of the following metals cannot be extracted by carbon reduction process

Options:
A $\mathrm{Pb}$
B $\mathrm{Al}$
C $\mathrm{Hg}$
D $\mathrm{Zn}$

The correct answer is:
$\mathrm{Al}$

Solution:
Al is highly electropositive. It can be obtained by electrolytic reduction.

Topic: Chemistry, General Principles and Processes of Isolation of Metals, JEE Main
Which of the following metals cannot be extracted by carbon reduction process

Options:
A Pb
B Al
C Hg
D Zn

The correct answer is:
Al

Solution:
Al is highly electropositive. It can be obtained by electrolytic reduction.

Topic: Chemistry, General Principles and Processes of Isolation of Metals, JEE Main