A unit cell of sodium chloride has four formula units. The edge length of the unit cell is 0.564 nm. What is the density of sodium chloride?

• 1.2 g/cm³

• 2.165g/cm³

• 3.64 g/cm³

• 4.56 g/cm³

The vapour pressure of pure benzene at a certain temperature is 0.850 bar. A non-volatile, non-electrolyte solid weighing 0.5 g is added to 39.0 g of benzene (molar mass 78 g/mol). The vapour pressure of the solution then is 0.845 bar. What is the molecular mass of the solid substance?

• 58

• 180

• 170

• 145

2.0 molar solution is obtained, when 0.5 mole solute is dissolved in :

• 250 ml solvent

• 250 g solvent

• 250 ml solution

• 1000 ml solvent

84.

What will be the normality of a solution, containing 4.9 g. H₃PO₄ dissolved in 500 ml water ?

• 0.3

• 1.0

• 3.0

• 0.1

Phenolphthalein is not suitable for the titration of :

• NaOH vs (COOH)₂

• KOH vs H₂SO₄

• K₂CO₃ vs HCl

• none of the above

36 g water and 828 g ethyl alcohol form an ideal solution. The mole fraction of water in it, is :

• 1.0

• 0.7

• 0.4

• 0.1

The weight of one molecule of a compound C₆₀H₁₂₀ is :

• 1.2 x 10^-20 g

• 5.025 x 10²³ g

• 1.4 x 10^-21 g

• 6.023 x 10²³ g

MnO${}_4^{2-}$ (1 mole) in neutral aqueous medium is disproportionated to

• 2/3 mole of MnO${}_4^{-}$ and 1/3 mole of MnO₂

• 1/3 mole of MnO${}_4^{-}$ and 2/3 mole of MnO₂

• 1/3 mole of Mn₂O₇ and 1/3 mole of MnO₂

• 2/3 mole of Mn₂O₇ and 1/3 mole of MnO₂

Assertion : Effusion rate of oxygen is smaller than nitrogen.

Reason: Molar mass of nitrogen is smaller than oxygen.

• If both assertion and reason are true and reason is the correct explanation of assertion

• If both assertion and reason are true but reason is not the correct explanation of assertion

• If assertion is true but reason is false

• If both assertion and reason are false.

How many litres of ammonia gas at S.T.P. would 1 be needed to prepare 100 ml of 2.5 M ammonium hydroxide solution?

• 5.6 L

• 0.056 L

• 11.2 L

• 0.56 L