General MCQ Chemistry Online

1.	Following is the substitution reaction in which ¾CN replaces ¾Cl R – Cl + R – CN + KCl To obtain propanenitrile, R-Cl should be (A) 1- chloropropane (B) chloroethane (C) 2-chloropropane (D) chloromethane	Answer: (B)
2.	For a chemical reaction of the type A Ý B, K = 2.0 and B Ý C, K = 0.01 Equilibrium constant for the reaction 2C Ý 2A is (A) 25 (B) 50 (C) 2500 (D) 4 ´ 10–4	Answer: (C)
3.	For a reaction A + B ® C + D if the concentration of A is doubled without altering the concentration of B, the rate gets doubled. lf the concentration of B is increased by nine times without altering the concentration of A, the rate gets tripled. The order of the reaction is (A) 2 (B) 1 (C) (D)	Answer: (C)
4.	For a reaction to be spontaneous at all temperatures (A) DG and DH should be negative (B) DG and DH should be positive (C) DG = DS = 0 (D) DH < DG	Answer: (A)
5.	For a reversible reaction : X(g) + 3Y(g) ⇌ 2Z(g) DH = -40 kJ the standard entropies of X, Y and Z arc 60, 40 and 50 JK-1 mol-1 respectively. The temperature at which the above reaction attains equilibrium is about (A) 400 K (B) 500 K (C) 273 K (D) 373 K	Answer: (B)
6.	For preparing a buffer solution of pH = 7.0, which buffer system you will choose? (A) H3 PO4 ,H2   (B) H2  , (C),   (D)H3 PO4 ,	Answer: (B)
7.	For the following reaction C6H12O6(aq) + H2(g) Ý C6H14O6(aq) Which one of the following is not affected by the addition of catalyst? (A) Rate of forward reaction (B) Rate of backward reaction (C) Time required to reach the equilibrium (D) Spontaneity	Answer: (D)
8.	For the given alkane The IUPAC name is (A) 1, 1 dimethyl-5-ethyl octane (B) 6-ethyl-2-methyl nonane (C) 4-ethyl-8-methyl nonane (D) 2-methyl, -6-propyl octane	Answer: (B)
9.	For the reactions I2(aq) Ý I2(oil) Equilibrium constant is K1 I2(oil) Ý  I2(ether) Equilibrium constant is K2 for the reaction I2(aq) Ý I2(ether) Equilibrium constant is K3 The relation between K1, K2, K3 is (A) K3 = K1 + K2 (B) K3 = K1K2 (C) K3 = K1/K2 (D) K3 = K2/K1	Answer: (B)
10.	For the reversible reaction, A(s) + B(g) ⇌ C(g) + D(g) ΔG° = -350 kJ, which one of the following statements is true? (A) The entropy change is negative (B) The reaction is thermodynamically nonfeasible (C) The reaction should be instantaneous (D) Equilibrium constant is greater then one.	Answer: (D)
11.	For transition metal octahedral complexes, the choice between high spin and low spin electronic configurations arises only for (A) d1 to d3 complexes (B) d4 to d7 complexes (C) d7 to d9 complexes (D) d1, d2 and d8 complexes	Answer: (B)
12.	Formic acid is a stronger acid than acetic acid. This can be explained using (A) –I effect (B) +M effect (C) –M effect (D) +I effect	Answer: (D)
13.	Generally, the first ionization energy increases along a period. But there are some exceptions. The one which is NOT an exception is ______. (A) Be and B (B) Na and Mg (C) Mg and Al (D) N and O	Answer: (B)
14.	Given a gas phase reaction 2A(g) + B(g) Ý C(g) + D(g) Which one of the following changes will affect the value of KC? (A) Addition of inert gas (B) Addition of catalyst (C) Addition of reactants (D) Increasing in temperature	Answer: (D)
15.	Given exothermic reaction (aq) + 6H2O(1) Ý [Co(H2O)]2+ +4CI- Which one of the following will decrease the equilibrium concentration of ? (A) Addition of HCI (B) Addition of Co(NO3)2 (C) The solution is diluted with water (D) The temperature is increased	Answer: (C)