According to the Arrhenius theory,which ion is produced when a base ionizes in water?

$A$ solution of a substance '$X$' is used for testing carbon dioxide. Identify '$X$'. What will be its reaction with carbon dioxide? Write a balanced equation for the reaction.

What is the molecular mass of $NaOH$?

$(a)$ Study the following chemical equation:
$CaSO_4 \cdot 2H_2O \xrightarrow{373K} CaSO_4 \cdot \frac{1}{2}H_2O + \frac{3}{2}H_2O$
Name the reactant and the product. State one use of the product.

What will be the action of the following substances on litmus paper? Dry $HCl$ gas,Moistened $NH_3$ gas,Lemon juice,Carbonated soft drink,Curd,Soap solution.

What are strong and weak acids? In the following list of acids,separate strong acids from weak acids: Hydrochloric acid,citric acid,acetic acid,nitric acid,formic acid,sulphuric acid.