The $pH$ of the gastric juices released during digestion is

$A$ metal compound $'A'$ reacts with dilute sulphuric acid to produce a gas which extinguishes a burning candle. Identify the compound $'A'$ and the gas produced. Write a balanced chemical equation for the reaction if one of the compounds formed in the reaction is sodium sulphate.

Which of the following are present in a dilute aqueous solution of hydrochloric acid?

Which of the following substances enters our body when a red ant bites us?

How is bleaching powder prepared? Why does bleaching powder $(i)$ not dissolve completely in water?

$R$. $K$. Patel,a chemistry teacher,explained the properties of inorganic acids in Std. $10$. He intentionally stated one of the properties incorrectly. Identify which one was wrong.