Which one of the following is not an amphoteric substance?

• HNO₃

• HCO${}_3^{-}$

• H₂O

• NH₃

The structure of orthophosphoric acid is

In the manufacture of ammonia by Haber's process, N₂ (g) + 3H₂ $\rightleftharpoons$2NH₃(g) + 92.3 KJ which of the following conditions is unfavourable ?

• Increasing the temperature

• Increasing the pressure

• Reducing the temperature

• Removing ammonia as it is formed

NH₃ and HCl gas are introduced simultaneously from the two ends of a long tube. A white ring of NH₃Cl appears first

• nearer to the HCl end

• at the centre of the tube

• throughout the tube

• nearer to the NH₃ end

Among the halogens, the one which is oxidised by nitric acid is

• Fluorine

• iodine

• chlorine

• bromine

The metal which does not form ammonium nitrate by reaction with dilute nitric acid is

• Al

• Fe

• Pb

• Mg

The elements with atmoic numbers 9, 17, 35, 53, 85, are all

• noble gases

• halogens

• heavy metals

• light metals

When chlorine is passed through warm benzene in presence of the sunlight, the product obtained is

• benzotrichloride

• chlorobenzene

• gammexane

• DDT

Ethyl benzoate reacts with PCl₅ to give

• C₂H₅Cl + C₆H₅COCl + POCl₃ + HCl

• C₂H₅Cl + C₆H₅COCl + POCl₃

• CH₃COCl + C₆H₅COCl + POCl₃

• C₂H₅Cl + C₆H₅COOH + POCl₃

250.

Urea is preferred to ammonium sulphate as a nitrogenous fertiliser because

• it is more soluble in wate

• it is cheaper than ammonium sulphate

• it is quite stable

• it does not cause acidity in the soil