Which of the following ions forms a highly soluble hydroxide in water?

The compound$(s)$ formed upon combustion of sodium metal in excess air is(are):

$Al$ vessels should not be cleaned with materials containing washing soda because .............

Which of the following oxides will not react with $NaOH$?

Give brief explanations on hydroxides of alkali metals.

What happens when : $(i)$ sodium metal is dropped in water? $(ii)$ sodium metal is heated in free supply of air? $(iii)$ sodium peroxide dissolves in water?