Question

An element 'x' reacts with oxygen to from oxide. This dioxide dissolves in water to form a solution which turns blue red. This oxide also reacts with naoh to form salt. The element 'x' is:

Answer 1

The element is carbon.

C + O2—>CO2

CO2+H2O—>H2CO3

which is acidic and turns blue litmus red.

CO2+2NaOH—>Na2CO3 +H2

so the element is carbon or C.