Which of the following statements is incorrect?

What is caused by an excess of $Na^+$ in the human body?

$A$ metal on combustion in excess air forms $X$. $X$ upon hydrolysis with water yields $H_2O_2$ and $O_2$ along with another product. The metal is

When a metal of group $1$ was dissolved in liquid ammonia,the following observations were obtained :
$(a)$ Blue solution was obtained initially.
$(b)$ On concentrating the solution,the blue colour changed to bronze colour.
How do you account for the blue colour of the solution? Give the name of the product formed on keeping the solution for some time.

When a small amount of sodium metal is dissolved in liquid ammonia at low temperature,which of the following does $NOT$ occur?

Which of the following is the most important biological compound containing $Mg$ found in the living world?