Solution 'X' contains Na₂CO₃ and NaHCO₃, 20 mL of X when titrated using methyl orange indicator consumed 60 mL of 0.1 M HCl solution. In another experiment, 20 mL of X solution when titrated using phenolphthalein, consumed 20 mL of 0.1 M HCl solution. The concentrations (in mol L^-1) of Na₂CO₃ and NaHCO₃ in X are respectively

• 0.01, 0.02

• 0.1, 0.1

• 0.01, 0.01

• 0.1, 0.01

The number of moles of electrons required to deposit 36 g of Al from an aqueous solution of Al(NO₃)₃ is (At. wt. of Al = 27)

• 4

• 3

• 2

• 1

383.

A carbon compound contains 12.8% of carbon, 21.% of hydrogen and 85.1% of bromine. The molecular weight of the compound is 187.9. Calculate the molecular formula of the compound.

(Atomic weight : H = 1.008; C = 12.0; Br = 79.9)

• CH₃Br

• CH₂Br₂I

• C₂H₄Br₂

• C₂H₃Br₃

3.011 × 10²² atoms of an element weight 1.15 gm. The atomic mass of the element is

• 23

• 10

• 16

• 35.5

A gas 'X' is dissolved in water at 2 bar pressure. Its mole fraction is 0.02 in solution. The mole fraction of water when the pressure of gas is doubled at the same temperature is

• 0.04

• 0.98

• 0.96

• 0.02

KMnO₄ reacts with KI in basic medium to form I₂ and MnO₂. When 250ml of 0.1M KI solution is mixed with 250ml of 0.02M KMnO₄ in basic medium, what is the number of moles of I₂ formed?

• 0.015

• 0.0075

• 0.005

• 0.01

The oxide of a metal contains 40% of oxygen. The valency of metal is 2. What is the atomic weight of metal?

• 24

• 13

• 40

• 36

Which of the following reactions does not take place?

• F₂ + 2Cl^- → 2F^- + Cl₂

• Br₂ + 2I^- → 2Br^- + I₂

• Cl₂ + 2Br^- → 2Cl^- + Br₂

• Cl₂ + 2F^- → 2Cl^- + F₂

What weight of hydrated oxalic acid should be added for complete neutralisation of 100 mL of 0.2 N -NaOH solution?

• 0.45 gm

• 0.90 gm

• 1.08 gm

• 1.26 gm

The number of moles of a solute in its solution is 20 and total number of moles are 80. The mole fraction of solute is

• 2.5

• 0.25

• 1

• 0.75