The number of grams/ weight of NH₄Cl required to be added to 3 litres of 0.01 M NH₃ to prepare the buffer of pH = 9.45 at temperature 298 K (K_b for NH₃ is 1.85 × 10^-5)

• 0.354 gm

• 4.55 gm

• 0.455 gm

• 3.55 gm

A 6% solution of sucrose C₂₂H₂₂O₁₁ is isotonic with 3% solution of an unknown organic substance. The molecular weight of unknown organic substance will be

• 684

• 171

• 100

• 342

503.

Commercially available H₂SO₄ is 98 g by H₂SO₄ and 2g by weight of water. It's density is 1.38 g cm^-3. Calculate the molality (m) of  H₂SO₄ (molar mass of  H₂SO₄  is 98 g mol^-1). 

• 500 m

• 20 molal

• 50 m

• 200 m

In order to oxidise a mixture of one mole of each of FeC₂O₄, Fe₂(C₂O₄)₃, FeSO₄ and Fe₂(SO₄)₃ in acidic medium, the number of moles of KMnO₄ required is:

• 1.5

• 3

• 2

• 1

The vapour pressures of pure liquids A and B are 400 and 600 mm Hg, respectively at 298 K. On mixing the two liquids, the sum of their initial volumes is equal to the volume of the final mixture. The mole fraction of liquid B is 0.5 in the mixture. The vapour pressure of the final solution, the mole fractions of components A and B in vapour phase, respectively are:

• 500 mm Hg, 0.4, 0.6

• 450 mm Hg, 0.4, 0.6

• 500 mm Hg, 0.5, 0.5

• 450 mm Hg, 0.5, 0.5

What would be the molality of 20% (mass / mass) aqueous solution of KI? (molar mass of KI = 166 g mol^-1)

• 1.08

• 1.35

• 1.51

• 1.48

The percentage composition of carbon by mole in methane is :

• 20%

• 25%

• 75%

• 80%

The strength of 11.2 volume solution of H₂O₂ is: [Given that molar mass of H=1 g mol^–1 and O=16 g mol^–1]

• 1.7%

• 34%

• 13.6%

• 3.4%

At 300k and 1 atmospheric pressure 10ml of a hydrocarbon required 55mL of O₂ for complete combustion and 40mL of CO₂ is formed. The formula of the hydrocarbon is:

• C₄H₆

• C₄H₇Cl

• C₄H₈

• C₄H₁₀

For a reaction, N₂ (g) + 3H₂ (g) → 2NH₃ (g); Identify dihydrogen (H₂) as a limiting reagent in the following reaction mixtures.

• 35 gm of N₂ + 8 gm of H₂

• 28 gm of N₂ + 6 gm of H₂

• 56 gm of N₂ + 10 gm of H₂

• 14 gm of N₂ + 4 gm of H₂