31g of ethylene glycol (C₂H₆O₂) is dissolved in 600 g of water. The freezing point depression of the solution is (K_f for water is 1.86 K kg mol^-1)

• 0.77 K

• 1.55 K

• 4.65 K

• 3.10 K

What are X and Y in the following reactions?

$$\begin{gathered} {\mathrm{MnO}}_4^{-} + {\mathrm{I}}^{-} \stackrel{{\mathrm{H}}^{+}}{\to } \mathrm{X} \\ {\mathrm{MnO}}_4^{-} + {\mathrm{I}}^{-} \stackrel{{\mathrm{H}}_2\mathrm{O}}{\to } \mathrm{Y} \end{gathered}$$

• ${\mathrm{I}}_2, {\mathrm{IO}}_4^{-}$

• ${\mathrm{I}}_2, {\mathrm{IO}}_3^{-}$

• ${\mathrm{IO}}_3^{-}, {\mathrm{IO}}_3^{-}$

• ${\mathrm{IO}}_3^{-},{\mathrm{I}}_2,$

Colloidal solution of gold is in different colours like red, purple, blue and golden because of

• variable oxidation states of gold

• size difference in the particles of gold

• presence of impurities

• difference in the concentration of gold particles

24.

Same amount of electricity is passed through aqueous solutions of AgNO₃ and CuSO₄. The number of Ag and Cu atoms deposited are x and y respectively. The correct  relationship between x and y is

• x <y 

• x= 2y

• x = y

• y = 2x

20% of a first order reaction was found to be completed at 10 a.m at 11.30 a.m. on the same day, 20% of the reaction was found to be remaining. The half life period in minutes of the reaction is

• 90

• 45

• 60

• 30

Two oxides of an non-metal X contain 50% and 40% of non-metal respectively. If the formula of the first oxide is XO₂. Then the formula of second oxide is

• X₂O₃

• X₂O₅

• XO₃

• X₂O

Copper matte contains

• CuO, FeS

• Cu₂S, FeS

• CuO, Cu₂S

• Cu₂S, FeO

S + Conc. H₂SO₄ → X + Y 

Here X is a gas and Y is a liquid and both are triatomic molecules. The number of electron lone pairs present on the central atoms of X and Y are respectively.

• 2,1

• 1,0

• 1,2

• 2,2

Which of the following is used in estimation of carbon monoxide?

• I₂O₄

• BrO₃

• Cl₂O₇

• I₂O₅

Which one ofthe following statements is not correct?

• In CO₂ molecule, carbon hybridisation is sp

• Fullerenes are made by heating graphite in an electric are in the presence of argon gas

• Both [SiF₆]^2- and [SiCl₆]^2- ions are known

• In CO molecule, there are one 'sigma' and two "pi" bonds