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University of Health Sciences UHS Lahore Past Paper of MCAT Chemistry

University of Health Sciences UHS Lahore Past Paper of MCAT Chemistry

1) it is experimentally found that catalyst is used to
a) lower the activation energy
b) increase the activation energy
c) lower the pH
d) decrease the temperature of other reactants

2) carbon exists as allotropes, which are different crystalline molecular forms of the same substance.
Graphite and diamond are allotropes of carbon. Diamond is non-conductor while graphite is conductor
a) graphite has a layered structure
b) in graphite all valence electrons are tetrahedrally bounded
c) in graphite one of the valence electron is free to move
d) graphite is soft and greasy

3) when the elements of group 2A are exposed to air , they quickly become coated with layer of oxide.
What is the purpose of this oxide layer
a) the oxide layer exposes the metal to atmospheric attack
b) the oxide layer increases the reactivity of metal
c) the oxide layer protects the metal from further attack
d) the oxide layer gives the metal a shiny look

4) hydrogenation of unsaturated oils is done by using
a) finally divided nickel
b) finally divided iron
c) vanadium pentaoxide
d) copper

5) tick the correct statement
a) chelates are more stable than ordinary complexes
b) ordinary complexes are more stable than chelates
c) monodentate ligand form chelate
d) chelates have no ring structure

6) in contact process the catalyst used for conversion of SO2 to SO3 is
a) magnesium oxide
b) Aluminium oxide
c) silicon dioxide
d) vanadium pentaoxide

7) the unpolluted rain water is slightly acidic due to reaction of rain water with
a) Sulphur dioxide
b) oxides of nitrogen
c) carbon dioxide
d) hydrocarbons present in air

8) the compound with an atom which has an unshared pair of electron is called
a) nucleophile
b) electrophile
c) protophile
d) none of these

9) 1-chloropropane and 2-chloropropane are isomers of each other. The type of isomerism between
them is
a) Cis-trans isomerism
b) chain isomerism
c) positional isomerism
d) functional group isomerism

10) benzene in presence of ACl3 gives acetophenone when reacts with
a) acetyl chloride
b) acetic acid
c) ethyl benzene
d) ethanoic acid

11) the substitution of –H group by –NO2 group in benzene is called
a) nitration
b) ammonolusis
c) sulphonation
d) reduction of benzene

12) when purely alcoholic solution of sodium/potassium hydroxide and halogenalkane are refluxed an
alkene is formed :
CH3-CH2-Br (in presence of alcoholic KOH )— > CH2=CH2
what is the mechanism of the reaction
a) elimination
b) dehydration
c) debromination
d) nucleophilic substitution

13) organic compound carbon tetra chloride is used as
a) lubricant
c) oxidant
d) plastic

14) an alcohol is converted into an aldehyde with same number of carbon atoms in the presence of
K2CrO4/H2SO4 . the alcohol is
a) CH2C(CH)2OH

15)in the mass spectrometer ; detector or collector measures the :
a)masses of isotopes
b)percentages of isotopes
c)relative abundances of isotopes
d)mass numbers of isotopes

16)how many chlorine atoms are in 2 moles of Cl :
a)2 x 6.022×10^23 atoms
b)35.5 x 6.022×10^23 atoms
c)2×10^23 atoms
d)2×6.02×10^22 atoms

17)boiling point of water is higher than petrol , because intermolecular forces in water are :
a)weaker than petrol
b)stronger than petrol
c)same as in petrol

18)DNA molecule is double stranded , in which two chains of DNA are twisted around each other by:
a)hydrogen bonds
b)Van der Waal’s forces
c)covalent bonds
d)dative bonds

19)the elements for which the value of ionization energy is low can:
a)gain electrons readily
b) gain electrons with difficulty
C)lose electron less readily
d) lose electron readily

20)the nature of cathode rays in discharge tube :
a)depends upon the nature of the gas used in discharge tube
b) depends upon the nature of the cathode used in discharge tube
c)is independent of the nature of the gas used in discharge tube
d) depends upon the nature of anode in the discharge tube

21)the ability of the atom in the covalent bond to attract the bonding electrons is called:
a)ionization energy
b)ionic bond energy
d)electron affinity

22)the paramagnetic character of substances is due to the presence of :
A)bond pairs of electrons
b)lone pairs of electrons
c)unpaired electrons in the atom or molecule
d)paired electrons in the valence shell of atoms

23)lattice energy of an ionic crystal is the enthalpy of:

24)mole fraction of any component is the ratio of moles of all components in a:

25)molarity is defined as the number of moles of solute of any substance dissolved:
a)per dm^3 of water
b)in one g of water
c)per m^3 of water
d)in 100 ml of water

26)in electrolytic cell a salt bridge is used in order to :
a)pass the electric current
b)prevent the flow of ions
c)mix solutions of two half cells
d)allow movement of ions b/w two cells

27)if in AgCl solution , some salt of NaCl is added , AgCl will be precipitated due to :
c)un saturation effect
d)common ion effect

28)if Ka for an acid is higher , the stronger is the acid , relate the strength of acid with pKa:
a)higher pKa , weaker the acid
b)lower pKa , stronger the acid
c)pKa has no relation with the strength of an acid
d)both a and b

29)according to the collision theory of bimolecular reactions in gas phase , minimum amount of energy
required for an effective collision is known as :
a)heat of reaction
b)rate of reaction
c)has no effect on the reaction
d)energy of activation

30) consider the following reaction:
R-CHO + 2[Ag(NH3))2]OH —– > RCOONH4 + 2Ag + 2NH3 + H2O
this reaction represents which of the following tests
a) Fehling test
b) benedict test
c) ninhydrin test
d) tollen’s test

31) a polymer in which the number of amino acid residue is greater than 100 or the molecular mass is
greater than 10,000 is called
a) protein
b) polypeptide
c) dipeptide
d) tripeptide

32) when hexanedioic acid is heated with hexamethylenediamine the compound formed is
a) polypeptide
b) ester
c) addition polymer
d) nylon 6,6

33) glucose and fructose are common example of
a) pentoses

b) hexoses
c) heptoses
d) butoses

34) the reaction between fats and caustic soda is called
a) hydrogenolysis
b) fermentation
c) carboxylation
d) saponification

35) macromolecules are defined as large molecules built up from small repeating units called
a) monomers
b) isomers
c) metamers
d) tautomers

36) PVC is an example of
a) addition polymer
b) condensation polymer
c) biopolymer
d) thermosetting polymer

37) Terylene, a polyester is an example of
a) biopolymer
b) lipids
c) condensation polymer
d) addition polymer

38) the suspected liver carcinogenic which also has a negative reproduction and developmental effects
in human is
a) iodoform
b) bromoform
c) chloroform
d) tropoform

39) peroxyacetylene is an irritant to human beings and it effects
a) ears
b) eyes
c) nose
d) stomach

40) which enzyme is involved in fermentation of glucose?
a) zymase
b) invertase
c) urease
d) diastase

41) relative acidic strength of alcohol , phenol , water and carboxylic acids is
a) carboxylic acid > alcohol > phenol > water
b) carboxylic acid > phenol > water > alcohol
c) phenol > carboxylic acid > alcohol > water
d) water > phenol > alcohol > carboxylic acid

42) in standard enthalpy of atmomization heat of surrounding
a) remains same
b) increases
c) decreases
d) increases then decreases

43) in all oxidation reactions, atoms of an element in a chemical species lose electrons and increases
a) oxidation state
b) reduction states
c) electrode
d) negative charges

44) in Haber process for manufacturing of ammonia , nitrogen is taken from
a) proteins occurring in living bodies
b) ammonium salts obtained industrially
c) air
d) minerals containing nitrates

45) in comparison to oxygen gas a strong triple covalent bond is present between nitrogen atoms in a
molecule and therefore nitrogen gas is:
a) highly reactive gas
b) completely inert like noble gases
c) very less reactive gas
d) moderately reactive gas

46) the –NH-CO group is called
a) amide group
b) amino group

c) protein linkage
d) peptide linkage

47) which of the following has an amino R group
a) lysine
b) proline
c) valine
d) alanine

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