Which of the following is a strong acid?

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

$A$ compound $X$ is a constituent of baking powder. It is used as an antacid. When $X$ is heated, it releases a gas $Y$ which, when passed through lime water, turns it milky, and a salt $Z$ is formed, which is the main constituent of washing powder. Identify $X, Y$, and $Z$. Write balanced chemical equations for the reactions involved.

$(i)$ What is the $pH$ range for a base?
$(ii)$ How can the strength of a basic solution be increased?

What is a universal indicator? State the purpose for which this indicator is used.

$NH_{4}Cl$ is a salt of which type?