Archives

Which of the following compounds will form a significant amount of meta product during the mono-nitration reaction?

Answer: (1)... View Article

On treatment of 100 mL of 0.1 M solution of CoCl₃.6H₂O with excess AgNO₃; 1.2 × 10²² ions are precipitated. The complex is :

1) [Co(H2O)6]Cl3 2) [Co(H2O)5Cl]Cl2.H2O 3) [Co(H2O)4Cl2]Cl.2H2O 4) [Co(H2O)3Cl3].3H2O Answer: (2) Millimoles of AgNO3 = [(1.2 x 1022) /... View Article

The most abundant elements by mass in the body of a healthy human adult are: Oxygen (61.4%); Carbon (22.9%), Hydrogen (10.0%); and Nitrogen (2.6%). The weight which a 75 kg person would gain if all ¹H atoms are replaced by ²H atoms is :

1) 7.5 kg 2) 10 kg 3) 15 kg 4) 37.5 kg Answer: (1) Mass of hydrogen = (10/100 ) * 75 = 7.5 kg Replacing 1H by 2H would replace 7.5 kg... View Article

Sodium salt of an organic acid ‘X’ produces effervescence with conc. H₂SO₄. ‘X’ reacts with the acidified aqueous CaCl₂ solution to give a white precipitate which decolourises the acidic solution of KMnO₄. ‘X’ is :

1) CH3COONa 2) Na2C2O4 3) C6H5COONa 4) HCOONa Answer: (2)... View Article

In the following reactions, ZnO is respectively acting as a/an :

(a) ZnO + Na2O → Na2ZnO2 (b) ZnO + CO2 → ZnCO3 1) acid and acid 2) acid and base 3) base and acid 4) base and base Answer: (2) In... View Article

The products obtained when chlorine gas reacts with cold and dilute aqueous NaOH are :

1) Cl− and ClO− 2) Cl− and ClO2 − 3) ClO− and ClO3− 4) ClO2− and ClO3 Answer: (1)... View Article

The group having isoelectronic species is :

1) O2−, F−, Na, Mg2+ 2) O−, F−, Na+, Mg2+ 3) O2−, F−, Na+, Mg2+ 4) O−, F−, Na, Mg+ Answer: (3) Mg2+, Na+, O2– and F– all have 10... View Article

A water sample has ppm level concentration of following anions

F- = 10; SO2-4 = 100; NO3- = 50 The anion/anions that make/makes the water sample unsuitable for drinking is/ are : 1) only F− 2) only SO2-4... View Article

Which of the following reactions is an example of a redox reaction?

1) XeF6 + H2O → XeOF4 + 2HF 2) XeF6 + 2H2O → XeO2 F2 + 4HF 3) XeF4 + O2 F2 → XeF6 + O2 4) XeF2 + PF5 → [XeF]+ PF6 − Answer: (3) Xe is... View Article

Which of the following species is not paramagnetic?

1) O2 2) B2 3) NO 4) CO Answer: (4) CO has 14 electrons (even) ∴ it is diamagnetic. NO has 15e– (odd) ∴ it is paramagnetic and has 1... View Article

Both lithium and magnesium display several similar properties due to the diagonal relationship; however, the one which is incorrect, is :

1) both form nitrides 2) nitrates of both Li and Mg yield NO2 and O2 on heating 3) both form basic carbonates 4) both form soluble... View Article

pK_aof a weak acid (HA) and pK_b of a weak base (BOH) are 3.2 and 3.4, respectively. The pH of their salt (AB) solution is :

1) 7.0 2) 1.0 3) 7.2 4) 6.9 Answer: (4) pH = 7 + [(1 / 2) (pKa - pKb)] = 7 + (1 / 2) [3.2 - 3.4] = 6.9... View Article

Two reactions R₁ and R₂ have identical pre-exponential factors. The activation energy of R₁ exceeds that of R₂ by 10 kJ mol⁻¹. If k₁ and k₂ are rate constants for reactions R₁ and R₂ respectively at 300 K, then ln (k₂/k₁) is equal to (R = 8.314 J mol⁻¹K⁻¹)

1) 6 2) 4 3) 8 4) 12 Answer: (2)... View Article

The radius of the second Bohr orbit for the hydrogen atom is : (Planck’s Constant. h = 6.6262 × 10⁻³⁴ Js; the mass of electron = 9.1091 × 10⁻³¹ kg; charge of electron e = 1.60210 × 10⁻¹⁹ C; permittivity of vacuum ∈₀= 8.854185 × 10⁻¹² kg⁻¹m⁻³A²)

1) 0.529 Å 2) 2.12 Å 3) 1.65 Å 4) 4.76 Å Answer: (2) r = a0 (n2 / Z) = 0.529 × 4 = 2.12 Å... View Article

The freezing point of benzene decreases by 0.45^oC when 0.2 g of acetic acid is added to 20 g of benzene. If acetic acid associates to form a dimer in benzene, percentage association of acetic acid in benzene will be : (K_f for benzene = 5.12 K kg mol⁻¹)

1) 74.6% 2) 94.6% 3) 64.6% 4) 80.4% Answer: (2) 0.45 = i (5.12) [(0.2 / 60) / 20] * 1000 i = 0.527 2CH3 COOH ⇋ [CH3 COOH]2 (1 - α) α... View Article

Which is the strongest reducing agent

1) Cr3+ 2) Cl− 3) Cr 4) Mn2+ Answer: (3) Positive E° is for Cr, hence it is the strongest reducing agent.... View Article

A metal crystallises in a face centred cubic structure. If the edge length of its unit cell is ‘a’, the closest approach between two atoms in metallic crystal will be:

1) √2 a 2) a/√2 3) 2a 4) 2√2 a Answer: (2) In FCC, one of the faces is like By △ABC, 2a2 = 16r2 r2 = (1 / 8) a2 r = 1 / 2√2 a... View Article

The Tyndall effect is observed only when the following conditions are satisfied:

(a) The diameter of the dispersed particles is much smaller than the wavelength of the light used. (b) The diameter of the dispersed particle is... View Article

∆U is equal to :

1) Adiabatic work 2) Isothermal work 3) Isochoric work 4) Isobaric work Answer: (1) For adiabatic process, q = 0 As per 1st law of... View Article

1 gram of a carbonate (M₂CO₃) on treatment with excess HCl produces 0.01186 moles of CO₂. The molar mass of M₂CO₃ in g mol⁻¹ is :

1) 118.6 2) 11.86 3) 1186 4) 84.3 Answer: (4) M2CO3 + 2HCl → 2MCl + H2O + CO2 = 84.3 g/mol... View Article