Which of the following gives the correct increasing order of acidic strength?

$15 \, mL$ of water and $10 \, mL$ of sulphuric acid are to be mixed in a beaker.
$(i)$ State the method that should be followed with reason.
$(ii)$ What is this process called?

The $pH$ scale is applicable to which of the following?

$A$ 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.

For making cake,baking powder is used. If at home your mother uses baking soda instead of baking powder in the cake,
$(a)$ how will it affect the taste of the cake and why?
$(b)$ how can baking soda be converted into baking powder?
$(c)$ what is the role of tartaric acid added to baking soda?

What will be the $pH$ of an aqueous solution of $NH_{4}Cl$?