The aqueous solution of an unknown sodium salt gives the following reactions.

I. It decolourises a solution of iodine in potassium iodide.

II. It gives white turbidity with dil.HCl solution.

III. It gives a white precipitate with AgNO₃ solution which changes colours and finally becomes black on standing.

The unknown sodium salt is

• Sodium thiosulphate

• sodium bisulphite

• sodium sulphite

• sodium sulphide

Which of the following would exert maximum osmotic pressure?

• Decinormal aluminium sulphate

• Decinormal barium chloride

• Decinormal sodium chloride

• A solution obtained by mixing equal volumes of (b) and (c) and filtering

The one which has least iodine value is

• sunflower oil

• ginger oil

• ghee

• groundnut oil

The vapour pressure of 100g water reduces from 3000 Nm^-2 to 2985 Nm^-2 when 5g of substance 'X' is dissolved in it. Substance 'X' is

• methanol

• glucose

• carbon dioxide

• cannot predict

The solubility of saturated solution of Ag₂CrO₄ is s mol L^-1. What is its solubility product?

• 4s³

• s³

• 2s³

• 16s²

The number of phase in a colloidal system is

• 1

• 2

• 3

• 4

Steel is heated to below red heat and then, cooled slowly. The process refers to

• hardening

• annealing

• tempering

• nitriding

Which does not give a precipitate with AgNO₃ solution?

• [Co(NH₃)₆]Cl₃

• [Co(NH₃)₅Cl]Cl₂

• [Co(NH₃)₄Cl₂]Cl

• [Co(NH₃)₃Cl₃]

At 25°C, the dissociation constant of a base, BOH, is 1.0 x 10^-12. The concentration of
hydroxyl ions in 0.01 M aqueous solution of the base would be

• 2.0 x 10^-6 mo L^-1

• 1.0 x 10^-5 mo L^-1

• 1.0 x 10^-6 mo L^-1

• 1.0 x 10^-7 mo L^-1

What is the correct relationship between the pHs of isomolar solutions of sodium oxide (pH₁), sodium sulphide (pH₂), sodium selenide (pH₃) and sodium telluride (pH₄)?

• pH₁ > pH₂ $\approx$pH₃ > pH₄

• pH₁ < pH₂ $<$pH₃ < pH₄

• pH₁ < pH₂ $<$pH₃ $\approx$ pH₄

• pH₁ > pH₂ $>$pH₃ > pH₄