S Block Elements

Two elements A and B have similar chemical properties. They don’t form solid hydrogencarbonates, but react with nitrogen to form nitrides. A and B, respectively, are :

The ionic mobility of alkali metal ions in aqueous solution is maximum for :

Based on lattice energy and other considerations which one of the following alkali metal chlorides is expected to have the highest melting point :

For a good quality cement, the ratio of lime to the total of the oxides of $\mathrm{Si}, \mathrm{Al}$ and $\mathrm{Fe}$ should be as close as to :

An alkaline earth metal ‘M’ readily forms water soluble sulphate and water insoluble hydroxide. Its oxide MO is very stable to heat and does not have rock-salt structure. M is :

Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R Assertion A : The alkali metals and their salts impart characteristic colour to reducing flame. Reason R : Alkali metals can be detected using flame tests. In the light of the above statements, choose the most appropriate answer from the options given below :

The metallic sodium disolves in liquid ammonia to form a deep blue coloured solution. The deep blue colour is due to formation of :

KO₂ (potassium super oxide) is used in oxygen cylinders in space and submarines because it :

Which of the following on thermal decomposition yields a basic as well as an acidic oxide?