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AIIMS MBBS Chemistry Question and Answer

chemistry in AIIMS MBBS exam

50 Multiple choice AIIMS Chemistry Question based on AIIMS MBBS Entrance Exam.

Question: Mixture of sand and sulphur may best be separated by
(a) Fractional crystallisation from aqueous solution
(b) Magnetic method
(c) Fractional distillation
(d) Dissolving in CS2 and filtering
Ans: (d)

Question: The species that does not contain peroxide ion is
(a) PbO2
(b) H2O2
(c) SrO2
(d) BaO2
Ans: (a)

Question: Irrespective of the source, pure sample of water always yields 88.89% mass of oxygen and 11.11% mass of hydrogen. This is explained by the law of
(a) Conservation of mass
(b) Constant composition
(c) Multiple proportions
(d) Constant volume
Ans: (b)

Question: Zinc sulphate contains 22.65% of zinc and 43.9% of water of crystallization. If the law of constant proportions is true, then the weight of zinc required to produce 20 g of the crystals will be
(a) 45.3 g
(b) 4.53 g
(c) 0.453 g
(d) 453 g
Ans: (b)

Question: The number of optical isomers of an organic compound having n asymmetric carbon atoms will be
(a) 2n + 1
(b) n2
(c) 2n
(d) 2n – 1
Ans: (c)

Question: Atoms consists of protons, neutrons and electrons. If the mass of neutrons and electrons were made half and two  times  respectively to their actual masses, then the atomic mass of 6C12
(a) Will remain approximately the same
(b) Will become approximately two  times
(c) Will remain approximately half
(d) Will be reduced by 25%
Ans: (d)

Question: The electronic configuration of a dipositive metal M2+ is 2, 8, 14 and its atomic weight is 56 a.m.u. The number of neutrons in its nuclei would be
(a) 30
(b) 32
(c) 34
(d) 42
Ans: (a)

Related: NEET Biology Questions

Question: The values of electronegativity of atoms A and B are 1.20 and 4.0 respectively. The percentage of ionic character of    A B bond is
(a) 50 %
(b) 43 %
(c) 55.3 %
(d) 72.24%
Ans: (d)

Question: O22– is the symbol of ….. ion
(a) Oxide
(b) Superoxide
(c) Peroxide
(d) Monoxide
Ans: (c)

Question: If ethylene, carbon monoxide and water is heated at high temperature, which of the following is formed
(a) C4H8O2
(b) C2H5COOH
(d) CH2 = CH – COOH
Ans. (b)

Question: A 0.2 molal aqueous solution of a weak acid (HX) is 20% ionised. The freezing point of this solution is (Given Kf = 1.86o C/m for water)
(a) –0.31oC
(c) –0.53oC
(d) –090oC
Ans: (b)

Question: The pyknometric density of sodium chloride crystal is 2.165 x 103 kgm–3 while its X-rays density is 2.178 x 103 kgm–3. The fraction of unoccupied sites in sodium chloride crystal is
(a) 5.96 x 10–3
(b) 5.96
(c) 5.96 x 10–2
(d) 5.96 x 10–1
Ans: (a)

Question: In which compound 8 : 8 coordination is found
(a) CsCl
(b) MgO
(c) Al2O3
(d) All of these
Ans: (a)

Question: At what temperature will the average speed of CH4 molecules have the same value as O2 has at 300 K
(a) 1200 K
(b) 150 K
(c) 600 K
(d) 300 K
Ans: (b)

Question: In amines, the hybridisation state of N is
(a) sp
(b) sp2
(c) sp3
(d) sp2d
Ans: (c)

Question: In an experiment during the analysis of a carbon compound, 145 l of H2 was collected at 760 mm Hg pressure and 27oC temperature. The mass of H2 is nearly
(a) 10 g
(b) 12 g
(c) 24 g
(d) 6 g
Ans: (b)

Question: Half-life of radium is 1580 yrs. Its average life will be
(a) 2.5 x 103 yrs
(b) 1.832 x 103 yrs
(c) 2.275 x 103 yrs
(d) 8.825 x 102 yrs
Ans: (c)

Question: The dissociation constant of two acids HA1 and HA2 are 3.14 x 10–4 and 1.96 x 10–5 respectively. The relative strength of the acids will be approximately
(a) 1 : 4
(b) 4 : 1
(c) 1 : 16
(d) 16 : 1
Ans: (b)

Question: An aqueous solution of ammonium acetate is
(a) Faintly acidic
(b) Faintly basic
(c) Fairly acidic
(d) Almost neutral
Ans: (d)

Question: In amines, the hybridisation state of N is
(a) sp
(b) sp2
(c) sp3
(d) sp2d
Ans: (c)

Question: To calculate the amount of work done in joules during reversible isothermal expansion of an ideal gas, the volume must be expressed in
(a) m3 only
(b) dm3 only
(c) cm3 only
(d) Any one of them
Ans: (d)

Question: The oxidation number of sulphur in S8, S2F2, H2S respectively, are
(a) 0, +1 and – 2
(b) + 2, +1 and – 2
(c) 0, + 1 and + 2
(d) – 2, + 1 and – 2
Ans: (a)

Related: AIIMS Biology Questions

Question: The elements which occupy the peaks of ionisation energy curve, are
(a) Na, K, Rb, Cs
(b) Na, Mg, Cl, I
(c) Cl, Br, I, F
(d) He, Ne, Ar, Kr
Ans: (d)

Question: Which is the correct order of ionic sizes (At. No. : Ce = 58, Sn = 50, Yb = 70 and Lu = 71)
(a) Ce > Sn > Yb > Lu
(b) Sn > Ce > Lu > Yb
(c) Lu > Yb > Sn > Ce
(d) Sn > Yb > Ce > Lu
Ans: (b)

Question: Which of the following statements is correct for CsBr3
(a) It is a covalent compound
(b) It contains Cs3+ and Br ions
(c) It contains Cs+ and Br3ions
(d) It contains Cs+, Brand lattice Br2 molecule
Ans: (c)

Question: A sudden large jump between the values of second and third ionisation energies of an element would be associated with the electronic configuration
(a) 1s2, 2s2 p6, 3s1
(b) 1s2, 2s2 p6, 3s2 p1
(c) 1s2, 2s2 p6, 3s2p2
(d) 1s2, 2s2 p6, 3s2
Ans: (d)

Question: Which element having following electronic configurations has minimum ionization potential
(a) 1s1
(b) 1s2, 2s2 2p6
(c) 1s2, 2s2 2p6, 3s1
(d) 1s2, 2s2 2p2
Ans: (c)

Question: Black Jack is an ore of
(a) Cr
(b) Sn
(c) Zn
(d) Ni
Ans: (c)

Question: Wolframite ore is separated from tinstone ore by the process of
(a) Roasting
(b) Electromagnetic
(c) Smelting
(d) Calcination
Ans: (b)

Question: A first order nuclear reaction is half completed in 45 minutes. How long does it need 99.9% of the reaction to be completed
(a) 5 hours
(b) 7.5 hours
(c) 10 hours
(d) 20 hours
Ans: (b)

Related: Multiple Choice Questions on Kingdom Protista

Question: Which process of reduction of mineral to the metal is suited for the extraction of copper from its ores with low copper content
(a) Metal displacement
(b) Auto reduction
(c) Chemical reduction
(d) Electrolytic reduction
Ans: (b)

Question: Hydrogen will not reduce
(a) Heated cupric oxide
(b) Heated ferric oxide
(c) Heated stannic oxide
(d) Heated aluminium oxide
Ans: (a)

Question: HCl is added to following oxides. Which one would give H2O2
(a) MnO2
(b) PbO2
(c) BaO
(d) None of these
Ans: (d)

Question: Which of the following pair will not produce dihydrogen gas
(a) Cu + HCl (dil.)
(b) Fe + H2SO4
(c) Mg + steam
(d) Na + alcohol
Ans: (a)

Question: Lead is maximum in
(a) Soda glass
(b) Jena glass
(c) Pyrex glass
(d) Flint glass
Ans: (d)

Question: If the concentration of CrO4ions in a saturated solution of silver chromate is 2 x 10–4. Solubility product of silver chromate will be
(a) 4 x 10–8
(b) 8 x 10–12
(c) 12 x 10–12
(d) 32 x 10–12
Ans: (d)

Question: BaSO4 and carbon on heating reacts to produce
(a) Ba + SO2 + CO2
(b) BaS + CO
(c) BaS + O2 + SO2
(d) BaCO3 + S + O2
Ans: (b)

Question: The atomic radii of alkali metals (M) lie in the order Li < Na < K < Rb but the radii of M+ ions in aqueous solution lie in the reverse order Li+ > Na+ > K+ > Rb+. What is the reason for this reverse order (on going from Li to Rb) ?
(a) Gradual increase in ionisation energy
(b) Increasing weakness of the metallic bond
(c) Increasing electropositive character
(d) Decreasing degree of hydration
Ans: (d)

Question: Transition metal with low oxidation number will act as
(a) A base
(b) An acid
(c) An oxidising agent
(d) None of these
Ans: (c)

Related: Newton’s Law and Gravitation Problems

Question: Which of the following pair will have effective magnetic moment equal
(a) Cr+3 and Mn+2
(b) Cr+2 and Fe+2
(c) V+2 and Sc+3
(d) Ti+2 and V+2
Ans: (b)

Question: Which is least soluble in water
(a) AgCl
(b) AgBr
(c) AgI
(d) Ag2S
Ans: (d)

Question: Which one of the following has the maximum number of unpaired electrons
(a) Mg2+
(b) Ti3+
(c) V3+
(d) Fe2+
Ans: (d)

Question: The rate law for a reaction between the substances A and B is given by, rate = k[A]n [B]m. On doubling the concentration of A and halving the concentration of B, the ratio of the new rate to the earlier rate of the reaction will be as
(a) ½(m + n)
(b) (m + n)
(c) (n – m)
(d) 2(n – m)
Ans: (d)

Question: The coordination number and oxidation state of Cr in K3 [Cr(C2O4)3] are, respectively
(a) 4 and +2
(b) 6 and +3
(c) 3 and +3
(d) 3 and 0
Ans: (b)

Question: Mixture is heated with dil. H2SO4 and the lead acetate paper turns black by the evolved gases. The mixture contains
(a) Sulphite
(b) Sulphide
(c) Sulphate
(d) Thiosulphate
Ans: (b)

Question: Total number of isomers of C6H14 are
(a) 4
(b) 5
(c) 6
(d) 7
Ans: (b)

Question: The hybridization state of carbon atoms in the product formed by the reaction of ethyl chloride with aqueous potassium hydroxide is
(a) sp
(b) sp2
(c) sp3
(d) sp3d
Ans: (c)

Question: The chief impurity present in red bauxite is :
(a) SiO2
(b) Fe2O3
(c) K2SO4
(d) NaF
Ans: (b)

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