Task: Text Categorization
Input (English): Question: The solubility of copper hydroxide in the presence of a high concentration of ammonia: 
 Options:  <0> Increased by formation of a complex ion of Cu2 + with NH3. <1> It is not affected because there is no common ion effect. <2> Decreases by common ion effect. <3> It decreases upon oxidation of bromide to molecular bromine. <4> It decreases because the hydroxides are more soluble in acidic medium.
Output (English): chemistry