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)

Free Online Chemistry Practical Mcqs

1.	Given reaction Y in the reaction is (A) Hexane (B) Cyclohexane (C) Cyclohexylcyclohexane (D) Cyclohexylether	Answer: (B)
2.	Given the following reactions involving A, B, C and D (i) C + B+ ® C+ + B (ii) A+ + D ® No reaction (iii) C+ + A ® No reaction (iv) D + B+ ® D+ + B The correct arrangement of A, B, C, D in order of their decreasing ability as reducing agent (A) D > B > C > A (B) A > C > D > B (C) C > A > B > D (D) C > A > D > B	Answer: (D)
3.	Glucose contains in addition to aldehyde group (A) one secondary OH and four primary OH groups (B) one primary OH and four secondary OH groups (C) two primary OH and three secondary OH groups (D) three primary OH and- two secondary OH groups	Answer: (B)
4.	H2S is passed into one dm3 of a solution containing 0.1 mole of Zn2+ and 0.01 mole of Cu2+ till the sulphide ion concentration reaches 8.1 ´ 10–19 moles. Which one of the following statements is true? [Ksp of ZnS and CuS are 3 ´ 10–22 and 8 ´ 10–36 respectively] (A) Both CuS and ZnS precipitate (B) Only ZnS precipitates (C) No precipitation occurs (D) Only CuS precipitates	Answer: (A)
5.	Hybridization of C2 and C3 of H3C – CH = C = CH – CH3 are (A) Sp, Sp3 (B) Sp2, Sp (C) Sp2, Sp2 (D) Sp, Sp	Answer: (B)
6.	Hydrogen bond is strongest in (A) S — H ——  O (B) O — H ——  S (C) F — H ——  F (D) O — H ——  N	Answer: (C)
7.	Hydrogen is prepared from H2O by adding (A) Ca, which acts as reducing agent (B) AI, which acts as oxidising agent (C) Ag, which acts as reducing agent (D) Au, which acts as oxidising agent	Answer: (A)
8.	Identify B and D is the following sequence of reactions. (A) Ethyl hydrogen sulphate and  alcoholic KOH (B) Methanol and bromoethane (C) Ethanol and alcoholic KOH (D) Ethyl hydrogen sulphate and aqueous KOH	Answer: (C)
9.	If the energies of the two photons are in the ratio of 3: 2, their wavelengths will be in the ratio of (A) 2: 3 (B) 9: 4 (C) 3: 2 (D) 1: 2	Answer: (A)
10.	If the molecular wt. of Na2S2O3 and I2 are M1 and M2 respectively, then what will be the equivalent wt. of Na2S2O3 and I2 in the following reaction? 2S2 + I2  ¾® S4 + 2I- (A) M1, M2 (B) M1, M2/2 (C) 2M1, M2 (D) M1,2M2	Answer: (B)
11.	In an alkaline medium, glycine predominantly exists as/in a /an (A) anion (B) cation (C) covalent form (D) zwitterions	Answer: (A)
12.	In aqueous solution glucose remains as (A) Only in open chain form (B) Only in pyranoze form (C) Only in furanose forms (D) In all three forms in equilibrium	Answer: (D)
13.	In chromite ore, the oxidation number iron and chromium are respectively ______. (A) +3, +6 (B) +3, +2 (C) +2, +3 (D) +2, +6	Answer: (C)
14.	In Ramsay and Rayleigh's isolation of noble gases from air, the nitrogen of the air is finally converted into (A) NO and NO2 (B) NaNO2 only (C) NaNO2 and NaNO3 (D) NaNO3 only	Answer: (C)
15.	In the conversion The sequence of the regents used are (A) (i) SOCl2 (ii)      (iii) H2O, heat (B) (i) SOCl2 (ii) NH3 (C) (i) SOCl2 (ii) NH3      (iii) Heat (D) (i) SOCl2 (ii) KCN      (iii) LiAlH	Answer: (A)

Chemistry Exam Preparation Questions and Answers

1.	An element belongs to Group 15 and third period of the periodic table. Its electonic configuration will be (A) 1s22s22p3 (B) 1s22s22p4 (C) 1s22s22p63s23p3 (D) 1s22s22p63s23p2	Answer: (C)
2.	An example for autocatalysis is (A) oxidation of NO to NO2 (B) oxidation of SO2 to SO3 (C) decomposition of KClO3 to KCl and O2 (D) oxidation of oxalic acid by acidified KMnO4	Answer: (D)
3.	Anhydrous ferric chloride is prepared by (A) Dissolving Fe(OH)3 in concentrated HCl (B) Dissolving Fe(OH)3 in dilute HCl (C) Passing dry HCl over heated iron scrap (D) Passing dry Cl2 gas over heated iron scrap	Answer: (D)
4.	At pH = 4 glycine exists as (A) H3 - CH2 - COO- (B) H3- CH2 - COO- (C) H2N - CH2 - COOH (D) H2N - CH2 - COO-	Answer: (B)
5.	By heating phenol with chloroform in alkali, it is converted into (A) salicylic acid (B) salicylaldehyde (C) anisole (D) phenyl benzoate	Answer: (B)
6.	Carbon cannot reduce Fe2O3 to Fe at a temperature below 983 K because ______. (A) CO is thermodynamically more stable then Fe2O3 (B) free energy change for the formation of CO is more negative then that of Fe2O3 (C) iron has higher affinity towards oxygen then carbon (D) carbon has higher affinity towards oxygen then iron	Answer: (C)
7.	Chemical reactions with very high Ea values are generally (A) very fast (B) very slow (C) moderately fast (D) spontaneous	Answer: (B)
8.	Consider the following gaseous equilibria with equilibrium constants K1 and K2 respectively. SO2 (g) + O2 (g) ⇌ SO3 (g) 2SO3 (g) ⇌ 2SO2 (g) + O2 (g) The equilibrium constants are related as ______. (A) (B) (C) (D)	Answer: (A)
9.	Decreasing order of reactivity of hydrogen halide acids in the conversion of ROH ® RX is (A) HCI > HBr > HI > HF (B) HI > HBr > HCI > HF (C) HF > HCI> HBr > HI (D) HF > HBr > HI > HCI	Answer: (B)
10.	During the adsorption of Krypton on activated charcoal at low temperature; ______. (A) ΔH > 0 and ΔS < 0 (B) ΔH < 0 and ΔS < 0 (C) ΔH < 0 and ΔS > 0 (D) ΔH > 0 and ΔS > 0	Answer: (B)
11.	During the fusion of an organic compound with sodium metal, nitrogen of the compound is converted into (A) NaNO2 (B) NaNH2 (C) NaCN (D) NaNC	Answer: (C)
12.	E1, E2 and E3 are the emfs of the following three galvanic cells respectively: (i) Zn (s) | Zn2+ (0.1 M) || Cu2+ (1M) | Cu (s) (ii) Zn (s) | Zn2+ (1 M) || Cu2+ (1M) | Cu (s) (iii) Zn (s) | Zn2+ (1 M) || Cu2+ (0.1M) | Cu (s) Which one of the following is true? (A) E1 > E2 > E3 (B) E2 > E1 > E3 (C) E3 > E2 > E1 (D) E3 > E1 > E2	Answer: (A)
13.	Equal weights of CH4 and H2 are mixed in a container at 25°C. Fraction of total pressure exerted by methane is (A) 1/2 (B) 1/3 (C) 1/9 (D) 8/9	Answer: (C)
14.	Ethyl benzene CANNOT be prepared by ______. (A) Wurtz-Fittig reaction (B) Wurtz reaction (C) Clemmensen reduction (D) Friedel-Crafts reaction	Answer: (B)
15.	Excess of silver nitrate solution is added to 100 ml of 0.01 M Pentaaqua chloro chromium (III) chloride solution. The mass of silver chloride obtained in grams is [Atomic mass of silver is 108] (A) 143.5 ´ 10-3 (B) 287 ´ 10-3 (C) 287 ´ 10-2 (D) 143.5 ´ 10-2	Answer: (B)

AIEEE Chemistry Practice Questions

1.	Based on the first law of thermodynamics, which one of the following is correct? (A) For an isochoric process, ΔU = -q (B) For an isochoric process, q = +w (C) For a cyclic process, q = -w (D) For an adiabatic process, ΔU = -w	Answer: (C)
2.	DG0 Vs T plot in the Ellingham's diagram slopes downwards for the reaction (A) Mg + O2 ® MgO (B) 2Ag + O2 ® Ag2O (C) C + O2 ® CO (D) CO + O2 ® CO2	Answer: (C)
3.	a-maltose consists of (A) two a-D-glucopyranose units with 1-2 glycosidic linkage (B) one a-D-glucopyranose units and one b-D-glucopyranose unit with 1-2 glycosidic linkage (C) two a-D-glucopyranose units with 1-4 glycosidic linkage (D) two b-D-glucopyranose units with 1-4 glycosidic linkage	Answer: (C)
4.	0.06 mole of KNO3 solid is added to 100 cm3 of water at 298 k. The enthalpy of KNO3aq solution is 35.8 kJmol-1. After the solute is dissolved the temperature of the solution will be (A) 293 k (B) 298 k (C) 301 k (D) 304 k	Answer: (A)
5.	1 × 10–3 m solution of Pt(NH3)4Cl4 in H2O shows depression in freezing point by 0.0054°C. The structure of the compound will be (Given Kfp(H2O) = 1.860 km–1) (A) [Pt(NH3)4]Cl4 (B) [Pt(NH3)3Cl]Cl3 (C) [Pt(NH3)2Cl2]Cl2 (D) Pt(NH3)Cl3]Cl	Answer: (C)
6.	1.2 g of organic compound on Kjeldahilization liberates ammonia which consumes 30 cm3 of 1 N HCl. The percentage of nitrogen in the organic compound is ______. (A) 35 (B) 30 (C) 20.8 (D) 46.67	Answer: (A)
7.	50 cm3 of 0.2 N HCl is titrated against 0.1 N NaOH solution. The titration was discontinued after adding 50 cm3 of NaOH. The remaining titration is completed by adding 0.5 N KOH. The volume of KOH required for completing the titration is (A) 12 cm3 (B) 10 cm3 (C) 21.0 cm3 (D) 16.2 cm3	Answer: (B)
8.	9.65 coulombs of electric current is passed through fused anhydrous MgCl2. The magnesium metal thus obtained is completely converted into a Grignard reagent. The number of moles of Grignard reagent obtained is (A) 1 ´ 10–4 (B) 5 ´ 10–4 (C) 1 ´ 10–5 (D) 5 ´ 10–5	Answer: (D)
9.	A buffer solution contains 0.1 mole of sodium acetate dissolved in 1000 cm3 of 0.1 M acetic acid. To the above buffer solution, 0.1 mole of sodium acetate is further added and dissolved. The pH of the resulting buffer is ______. (A) pKa + 1 (B) pKa (C) pKa + Log 2 (D) pKa = Log 2	Answer: (C)
10.	A chemical reaction proceeds into the following steps Step I, 2A Ý X fast Step II, X + B Ý  Y slow Step III, Y + B Ý Product fast The rate law for the overall reaction is (A) Rate = k[A]2 (B) Rate = k[B]2 (C) Rate = k[A][B] (D) Rate = k[A]2[B]	Answer: (D)
11.	A mixture of CaCl2 and NaCl weighing 4.44 g is treated with sodium carbonate solution to precipitate all the calcium ions as calcium carbonate. The calcium carbonate so obtained is heated strongly to get 0.56 g of CaO. The percentage of NaCl in the mixture is [Atomic mass of Ca = 40] (A) 75 (B) 31.5 (C) 40.2 (D) 25	Answer: (A)
12.	A plot of In k against (abscissa) is expected to be a straight line with intercept on ordinate axis equal to (A) (B) (C) (D) R ´ DS°	Answer: (B)
13.	A radioactive atom  emits two a particles and one b particle successively. The number of neutrons in the nucleus of the product will be (A) X – 4 – Y (B) X – Y – 5 (C) X – Y – 3 (D) X – Y – 6	Answer: (B)
14.	A solution is 0.1 M with respect to Ag+, Ca2+, Mg2+ and AI3+ which will precipitate at lowest concentration of  [] when solution of Na3PO4 is added? (A) Ag3PO4(Ksp = 1 × 10–6) (B) Ca3(PO4)2(Ksp = 1 × 10–33) (C) Mg3(PO4)2(Ksp = 1 × 10–24) (D) AIPO4(Ksp = 1 × 10–20)	Answer: (D)
15.	A solution of two liquids boils at a temperature more than the boiling point of either of them. Hence, the binary solution shows (A) positive deviation from Raoult's law (B) negative deviation from Raoult's law (C) positive or negative deviation from Raoult's law depending upon the composition (D) no deviation from Raoult's law	Answer: (B)