SSC CGL Chemistry Questions and Answers – Page 4

rder decreases so entropy decreases. Other processes increase entropy. Option A (“Melting of ice”) is incorrect because it does not satisfy the chemical formula, reaction, periodic trend, numerical relation, oxidation state or definition required by the question. Option B (“Vaporization of water”) is incorrect because it does not satisfy the chemical formula, reaction, periodic trend, numerical relation, oxidation state or definition required by the question. Option C (“Dissolution of salt in water”) is incorrect because it does not satisfy the chemical formula, reaction, periodic trend, numerical relation, oxidation state or definition required by the question. The answer field, correct index and explanation therefore all identify Crystallization from solution. Crystallization is an ordering process where disorder decreases so entropy decreases.

Option A (“NH3”) is incorrect because it does not satisfy the chemical formula, reaction, periodic trend, numerical relation, oxidation state or definition required by the question. Option D (“H2O”) is incorrect because it does not satisfy the chemical formula, reaction, periodic trend, numerical relation, oxidation state or definition required by the question. CO is a pi-acceptor ligand (pi-back bonding).

issociate so basicity is 2 (dibasic acid). H3PO3 has 2 P-OH groups and 1 P-H bond. Only P-OH groups dissociate so basicity is 2 (dibasic acid).

Option B (“RLiX”) is incorrect because it does not satisfy the chemical formula, reaction, periodic trend, numerical relation, oxidation state or definition required by the question. Option C (“RZnX”) is incorrect because it does not satisfy the chemical formula, reaction, periodic trend, numerical relation, oxidation state or definition required by the question. Option D (“RNaX”) is incorrect because it does not satisfy the chemical formula, reaction, periodic trend, numerical relation, oxidation state or definition required by the question. The answer field, correct index and explanation therefore all identify RMgX. Grignard reagent has formula RMgX where R is alkyl group Mg is magnesium and X is halogen.

Option A (“CH3Cl with NaOH”) is incorrect because it does not satisfy the chemical formula, reaction, periodic trend, numerical relation, oxidation state or definition required by the question. Option B (“CH3CH2Cl with NaOH”) is incorrect because it does not satisfy the chemical formula, reaction, periodic trend, numerical relation, oxidation state or definition required by the question. Option D (“CH2=CHCH2Cl with NaOH”) is incorrect because it does not satisfy the chemical formula, reaction, periodic trend, numerical relation, oxidation state or definition required by the question. Identify the governing formula, definition or reaction and apply it consistently. The answer field, correct index and explanation therefore all identify (CH3)3CCl with NaOH.(CH3)3CCl undergoes SN1 mechanism as tertiary carbocation formed is very stable.

ation with conc H2SO4 to form ethylene (CH2=CH2). Option A (“Ethane”) is incorrect because it does not satisfy the chemical formula, reaction, periodic trend, numerical relation, oxidation state or definition required by the question. Option B (“Diethyl ether”) is incorrect because it does not satisfy the chemical formula, reaction, periodic trend, numerical relation, oxidation state or definition required by the question. Option D (“Acetaldehyde”) is incorrect because it does not satisfy the chemical formula, reaction, periodic trend, numerical relation, oxidation state or definition required by the question. The answer field, correct index and explanation therefore all identify Ethylene. At 170 degree C ethanol undergoes dehydration with conc H2SO4 to form ethylene (CH2=CH2).

Option A (“CH3NC”) is incorrect because it does not satisfy the chemical formula, reaction, periodic trend, numerical relation, oxidation state or definition required by the question. Option C (“CH3OH”) is incorrect because it does not satisfy the chemical formula, reaction, periodic trend, numerical relation, oxidation state or definition required by the question. Option D (“CH3NH2”) is incorrect because it does not satisfy the chemical formula, reaction, periodic trend, numerical relation, oxidation state or definition required by the question. Identify the governing formula, definition or reaction and apply it consistently. The answer field, correct index and explanation therefore all identify CH3CN. CH3Br + KCN gives CH3CN (methyl cyanide/acetonitrile).

ipoles cancel giving zero net dipole moment. Option A (“H2O”) is incorrect because it does not satisfy the chemical formula, reaction, periodic trend, numerical relation, oxidation state or definition required by the question. Option B (“NH3”) is incorrect because it does not satisfy the chemical formula, reaction, periodic trend, numerical relation, oxidation state or definition required by the question. The answer field, correct index and explanation therefore all identify BF3. BF3 is a planar trigonal molecule. Due to its symmetrical geometry the individual bond dipoles cancel giving zero net dipole moment.

served in colloids like milk starch solution fog. Option A (“True solutions”) is incorrect because it does not satisfy the chemical formula, reaction, periodic trend, numerical relation, oxidation state or definition required by the question. Option C (“Suspensions”) is incorrect because it does not satisfy the chemical formula, reaction, periodic trend, numerical relation, oxidation state or definition required by the question. Option D (“Both colloids and suspensions”) is incorrect because it does not satisfy the chemical formula, reaction, periodic trend, numerical relation, oxidation state or definition required by the question. Identify the governing formula, definition or reaction and apply it consistently. The answer field, correct index and explanation therefore all identify Colloids. Tyndall effect (scattering of light by colloidal particles) is observed in colloids like milk starch solution fog.

NH3 is a base (proton acceptor). Option A (“NaCl”) is incorrect because it does not satisfy the chemical formula, reaction, periodic trend, numerical relation, oxidation state or definition required by the question. Option B (“NH3”) is incorrect because it does not satisfy the chemical formula, reaction, periodic trend, numerical relation, oxidation state or definition required by the question. Option D (“BF3”) is incorrect because it does not satisfy the chemical formula, reaction, periodic trend, numerical relation, oxidation state or definition required by the question. The answer field, correct index and explanation therefore all identify HCl. HCl donates a proton (H+) in solution making it a Bronsted-Lowry acid.