21.

Glauber's salt is

• Na₂SO₄.10H₂O

• Na₂S₂O₃.5H₂O

• CuSO₄.5H₂O

• Na₂B₄O₇.10H₂O

Propyne on passing through red hot copper tube forms

• benzene

• toluene

• mesitylene

• None of these

Which one of the following is mainly responsible for depletion of ozone layer?

• Methane

• Carbon dioxide

• Water

• Chlorofluorocarbons

On warming with silver powder, chloroform is converted into

• acetylene

• hexachloroethane

• 1, 1, 2, 2-tetrachloroethane

• ethylene

Hydrogen molecule differs from chlorine molecule in the following respect.

• Hydrogen molecule is non-polar but chlorine molecule is polar

• Hydrogen molecule is polar while chlorine molecule is non-polar

• Hydrogen molecule can form intermolecular hydrogen bonds but chlorine molecule does not

• Hydrogen molecule cannot participate in coordinate bond formation but chlorine molecule can

Which of the following metal carbonates decomposes on heating?

• MgCO₃

• Na₂CO₃

• K₂CO₃

• Rb₂CO₃

Which one of the following has a coordinate bond?

• NH₄Cl

• AlCl₃

• NaCl

• Cl₂

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

Cow milk, an example of natural emulsion, is stabilised by

• fat

• water

• casein

• Mg²⁺ ions

For a zero order reaction

• ${\mathrm{t}}_{\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.} \propto {\mathrm{R}}_0$

• ${\mathrm{t}}_{\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.} \propto \frac{1}{{\mathrm{R}}_0}$

• ${\mathrm{t}}_{\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.} \propto {\mathrm{R}}_0^2$

• ${\mathrm{t}}_{\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.} \propto \frac{1}{{\mathrm{R}}_0^2}$