Some Basic Concepts of Chemistry

In acid medium, Zn reduces nitrate ion to NH${}_4^{+}$ ion according to the reaction,

Zn + NO${}_3^{-}$→ Zn²⁺ + NH${}_4^{+}$ + H₂O (unbalanced).

How many moles of HCl are required to reduce half a mole of NaNO₃ completely ? Assume the availability of sufficient Zn.

• 5

• 4

• 3

• 2

The relative lowering of vapour pressure of a dilute aqueous solution containing non-volatile solute is 0.0125. The molality of the solution is about

• 0.70

• 0.50

• 0.90

• 0.80

0.1 mole of a carbohydrate with empirical formula CH₂O contains 1 g of hydrogen. What is its molecular formula?

• C₂H₄O₂

• C₅H₁₀O₅

• C₃H₆O₃

• C₆H₁₂O₆

Commercial 11.2 volume H₂O₂ solution has a molarity of :

• 1.0

• 0.5

• 11.2

• 1.12

100 g CaCO₃ is treated with 1 L of 1N HCl. What would be the weight of CO₂ liberated after the completion of the reaction ?

• 55 g

• 11 g

• 22 g

• 33 g

What is the volume (in litres) of oxygen required at STP to completely convert 1.5 mol of sulphur into sulphur dioxide?

• 11.2

• 22.4

• 33.6

• 44.8

The volume of 0.1 M H₂SO₄ that is needed to completely neutralise 30mL of 0.2 M NaOH solution, is

• 15mL

• 30mL

• 40mL

• 60mL

The empirical formula of a compound is CH₂. One mole of this compound has a mass 42g. Its molecular formula is

• C₃H₆

• C₂H₆

• CH₂

• C₂H₂

What is the volume of "20 volume H₂O₂" required to get 5000 cm³ of oxygen at STP?

• 250 cm³

• 50 cm³

• 100 cm³

• 125 cm³

The decomposition of a certain mass of CaCO₃ gave 11.2 dm³ of CO₂ gas at STP. The mass of KOH required to completely neutralise the gas is :

• 56 g

• 28 g

• 42 g

• 20 g