Which of the following is an oxide of metal?

Calcium phosphate is present in tooth enamel. Its nature is

How do metal carbonates and metal hydrogen carbonates react with acids? Give their chemical equations. Name the gas evolved during the reaction. What will happen when this gas is passed through lime water?

How does chloride of lime differ chemically from calcium chloride?

What will be the value of $pH$ if blue litmus paper turns red in an aqueous solution?

$A$ metal $M$ forms an oxide with the formula $M_{2}O_{3}$. It dissolves in both dilute sulphuric acid and dilute sodium hydroxide solution. Identify the metal and write the chemical equations for the reactions involved.