<PAGE>


[Unless this certificate is presented by an authorized representative of The
Depository Trust Company, to the issuer or its agent for registration of
transfer, exchange or payment, and any certificate issued is registered in the
name of Cede & Co. or such other name as is requested by an authorized
representative of The Depository Trust Company (and any payment is made to Cede
& Co. or to such other entity as is requested by an authorized representative of
The Depository Trust Company, ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE
OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL since the registered owner hereof,
Cede & Co., has an interest herein.]

[THIS SECURITY IS A GLOBAL SECURITY AS REFERRED TO IN THE INDENTURE HEREINAFTER
REFERENCED. UNLESS AND UNTIL IT IS EXCHANGED IN WHOLE OR IN PART FOR THE
INDIVIDUAL SECURITIES REPRESENTED HEREBY, THIS GLOBAL SECURITY MAY NOT BE
TRANSFERRED EXCEPT AS A WHOLE BY THE DEPOSITARY TO A NOMINEE OF THE DEPOSITARY
OR BY A NOMINEE OF THE DEPOSITARY TO THE DEPOSITARY OR ANOTHER NOMINEE OF THE
DEPOSITARY OR BY THE DEPOSITARY OR ANY SUCH NOMINEE TO A SUCCESSOR DEPOSITARY OR
A NOMINEE OF SUCH SUCCESSOR DEPOSITARY.]

                         QUESTAR MARKET RESOURCES, INC.


                           ___% Senior Notes Due 20__


No._______                                                             $

                  QUESTAR MARKET RESOURCES, INC., a corporation duly organized
and existing under the laws of Utah (herein called the "Company," which term
includes any successor corporation under the Indenture hereinafter referred to),
for value received, hereby promises to pay to or duly provide for
______________, or registered assigns, the principal sum of __________________
on ________, 20__


<PAGE>


and to pay interest thereon from _________, 2000 or from the most recent
Interest Payment Date to which interest has been paid or duly provided for,
semi-annually on May 1 and November 1 in each year, commencing ___________,
2000, at the rate of ___% per annum, until the principal hereof is paid or made
available for payment, and (to the extent that the payment of such interest
shall be legally enforceable) at the rate of ___ % per annum on any overdue
principal and premium and on any overdue installment of interest. The interest
so payable, and punctually paid or duly provided for, on any Interest Payment
Date will, as provided in the Indenture, dated as of _______, 2000 (herein
called the "Indenture"), between the Company and Bank One Trust Company, NA,
as Trustee (herein called the "Trustee"), be paid to the Person in whose name
this Security (or one or more Predecessor Securities) is registered at the close
of business on the Regular Record Date for such interest, which shall be the
April 15 or October 15 (whether or not a Business Day), as the case may be, next
preceding such Interest Payment Date. Any such interest not so punctually paid
or duly provided for will forthwith cease to be payable to the Holder on such
Regular Record Date and may either be paid to the Person in whose name this
Security (or one or more Predecessor Securities) is registered at the close of
business on a Special Record Date for the payment of such Defaulted Interest to
be fixed by the Trustee, notice whereof shall be given to Holders of Securities
of this series not less than 10 days prior to such Special Record Date, or be
paid at any time in any other lawful manner not inconsistent with the
requirements of any securities exchange on which the Securities of this series
may be listed, and upon such notice as may be required by such exchange, all as
more fully provided in said Indenture.

                  Payment of the principal of (and premium, if any) and interest
on this Security will be made at the office or agency of the Company in the city
of Chicago, Illinois or The City of New York maintained for such purpose, and at
any other


                                        2

<PAGE>


office or agency maintained by the Company for such purpose, in such coin or
currency of the United States of America as at the time of payment is legal
tender for payment of public and private debts; provided, however, that at the
option of the Company payment of interest may be made by check mailed to the
address of the Person entitled thereto as such address shall appear in the
Security Register.

                  This Security is one of a duly authorized issue of securities
of the Company (herein called the "Securities"), issued and to be issued in one
or more series under the Indenture, to which Indenture and all indentures
supplemental thereto reference is hereby made for a statement of the respective
rights, limitations of rights, duties and immunities thereunder of the Company,
the Trustee and the Holders of the Securities and of the terms upon which the
Securities are, and are to be, authenticated and delivered. This Security is one
of the series designated above, limited in aggregate principal amount to
$150,000,000.

                  The Securities of this series are subject to redemption upon
not less than 30 days' notice by mail, at any time, as a whole or in part, at
the election of the Company, at a Redemption Price equal to the principal amount
plus the Make Whole Amount, together with accrued interest to the Redemption
Date, but interest installments whose Stated Maturity is on or prior to such
Redemption Date will be payable to the Holders of such Securities, or one or
more Predecessor Securities, of record at the close of business on the relevant
Record Dates referred to above, all as provided in the Indenture. As used herein
the following terms will have the definitions given below:

                  "Make-Whole Amount" for any Security means an amount equal to
the excess, if any, of (a) the present value of the remaining principal and
interest payments on such Security through the Stated Maturity thereof, computed
using a


                                        3

<PAGE>


discount rate equal to the Treasury Rate plus ________________ basis points,
over (b) the outstanding principal amount of such Security.

                  "Treasury Rate" means, at any date of determination, the yield
to maturity as of such date (as compiled by and published in the most recent
Federal Reserve Statistical Release H.15 (519), which has become publicly
available at least two business days prior to the date of the redemption notice
for which such computation is being made, or if such Statistical Release is no
longer published, as reported in any publicly available source of similar market
data) of United States Treasury securities with a constant maturity most nearly
equal to the Make-Whole Average Life; provided, however, that if the Make-Whole
Average Life is not equal to the constant maturity of the United States Treasury
security for which a weekly average yield is given, the Treasury Rate shall be
obtained by linear interpolation (calculated to the nearest one-twelfth of a
year) from the weekly average yields of United States Treasury securities for
which such yields are given, except that if the Make-Whole Average Life is less
than one year, the weekly average yield on actually traded United States
Treasury securities adjusted to a constant maturity of one year shall be used.

                  "Make Whole Average Life" means, with respect to any date of
redemption for any Security, the number of years (calculated to the nearest one-
twelfth) from such redemption date to the Stated Maturity of such Security.

                  In the event of redemption of this Security in part only, a
new Security or Securities of this series and of like tenor for the unredeemed
portion hereof will be issued in the name of the Holder hereof upon the
cancellation hereof.

                  If an Event of Default with respect to Securities of this
series shall occur and be continuing, the principal of the Securities of this
series may be declared due and payable in the manner and with the effect
provided in the Indenture.


                                        4

<PAGE>


                  The Indenture permits, with certain exceptions as therein
provided, the amendment thereof and the modification of the rights and
obligations of the Company and the rights of the Holders of the Securities of
each series to be affected under the Indenture at any time by the Company and
the Trustee with the consent of the Holders of 66 2/3% in principal amount of
the Securities at the time Outstanding of each series to be affected. The
Indenture also contains provisions permitting the Holders of specified
percentages in aggregate principal amount of the Securities of each series at
the time Outstanding, on behalf of the Holders of all Securities of such series,
to waive compliance by the Company with certain provisions of the Indenture and
certain past defaults under the Indenture and their consequences. Any such
consent or waiver by the Holder of this Security shall be conclusive and binding
upon such Holder and upon all future Holders of this Security and of any
Security issued upon the registration of transfer hereof or in exchange herefor
or in lieu hereof, whether or not notation of such consent or waiver is made
upon this Security.

                  No reference herein to the Indenture and no provision of this
Security or of the Indenture shall alter or impair the obligation of the
Company, which is absolute and unconditional, to pay the principal of (and
premium, if any) and interest on this Security at the times, place and rate, and
in the coin or currency, herein prescribed.

                  As provided in the Indenture and subject to certain
limitations therein set forth, the transfer of this Security is registerable in
the Security Register, upon surrender of this Security for registration of
transfer at the office or agency of the Company in any place where the principal
of (and premium, if any) and interest on this Security are payable, duly
endorsed by, or accompanied by a written instrument of transfer in form
satisfactory to the Company and the Security Registrar duly executed by, the
Holder hereof or his attorney duly authorized in writing, and


                                        5

<PAGE>


thereupon one or more new Securities of this series and of like tenor, of
authorized denominations and for the same aggregate principal amount, will be
issued to the designated transferee or transferees.

                  The Securities of this series are issuable only in registered
form without coupons in denominations of $1,000 and any integral multiple
thereof. As provided in the Indenture and subject to certain limitations therein
set forth, Securities of this series are exchangeable for a like aggregate
principal amount of Securities of this series and of like tenor of a different
authorized denomination, as requested by the Holder surrendering the same.

                  No service charge shall be made for any such registration of
transfer or exchange, but the Company may require payment of a sum sufficient to
cover any tax or other governmental charge payable in connection therewith.

                  Prior to due presentment of this Security for registration of
transfer, the Company, the Trustee and any agent of the Company or the Trustee
may treat the Person in whose name this Security is registered as the owner
hereof for all purposes, whether or not this Security be overdue, and neither
the Company, the Trustee nor any such agent shall be affected by notice to the
contrary.

                  All terms used in this Security which are defined in the
Indenture shall have the meanings assigned to them in the Indenture.

                  Unless the certificate of authentication hereon has been
executed by the Trustee by manual signature, this Security shall not be entitled
to any benefit under the Indenture or be valid or obligatory for any purpose.


                                        6

<PAGE>


                  IN WITNESS WHEREOF, the Company has caused this instrument
to be duly executed under its corporate seal.
Dated:

                                       QUESTAR MARKET RESOURCES, INC.

                                       By
                                         ----------------------------------


Attest:


----------------------------





                     TRUSTEE'S CERTIFICATE OF AUTHENTICATION

                  This is one of the Securities of the series designated therein
referred to in the within-mentioned Indenture.

                                       BANK ONE TRUST COMPANY, NA
                                       as Trustee

                                       By
                                         ----------------------------------
                                                 Authorized Signature


                                        7