Some Basic Concepts of Chemistry

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

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

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

Liquid ‘M’ and liquid ‘N’ form an ideal solution. The vapour pressures of pure liquids ‘M’ and ‘N’ are 450 and 700mm Hg, respectively, at the same temperature. Then correct statement is:

(x_M = Mole fraction of 'M' is solution; x_N = Mole fraction of 'N' in solution; y_M = Mole fraction of 'M' in vapour phase; y_N = Mole fraction of 'N' in vapour phase)

• $\frac{{\mathrm{x}}_{\mathrm{M}}}{{\mathrm{x}}_{\mathrm{N}}} < \frac{{\mathrm{y}}_{\mathrm{M}}}{{\mathrm{y}}_{\mathrm{N}}}$

• $\frac{{\mathrm{x}}_{\mathrm{M}}}{{\mathrm{x}}_{\mathrm{N}}} = \frac{{\mathrm{y}}_{\mathrm{M}}}{{\mathrm{y}}_{\mathrm{N}}}$

• $\frac{{\mathrm{x}}_{\mathrm{M}}}{{\mathrm{x}}_{\mathrm{N}}} > \frac{{\mathrm{y}}_{\mathrm{M}}}{{\mathrm{y}}_{\mathrm{N}}}$

• (x_M - y_M) < (x_N - y_N)