When NaCl is dissolved in water , the sodium ions becomes :

• oxidised

• reduced

• hydrolysed

• hydrated

The temporary hardness of water due to calcium bicarbonate can be removed by adding :

• CaCO₃

• Ca(OH)₂

• CaCl₂

• HCl

Which one does not form oxide on heating ?

• ZnCO₃

• CaCO₃

• Li₂CO₃

• Na₂CO₃

The compound which does not exist as hydrate form

• ferrous sulphate

• copper sulphate

• magnesium sulphate

• sodium chloride

425.

Which of the following acids will not evolve H₂ gas on reaction with alkali metals?

• Hydrazoic acid

• Perxenic acid

• Boric acid

• None of these

Metals are good conductor of electricity because they contain :

• a network structure

• ionic bonds

• very few valence electrons

• free electrons

Which of the following fluorides has the lowest melting point?

• BaF₂

• SrF₂

• CaF₂

• BeF₂

Which of the following has the highest tendency to give the reaction,

M⁺_(g) $\underset{\mathrm{medium}}{\overset{\mathrm{aqueous}}{\to }}$ M⁺_(aq.) ?

• Na

• Li

• K

• Rb

Among the following components of cement which is present in highest amount?

• Ca₂SiO₄

• Ca₃SiO₅

• Al₂O₃

• Ca₃Al₂O₆

Radioactive metal is :

• Li

• Ce

• Na

• Ra