Ishaan tested the nature of a few common substances with different indicators and recorded his observations as follows:

Substance $\mathrm{P}$ turned methyl orange yellow.

Substance $\mathrm{Q}$ turned phenolphthalein colourless.

Substance $\mathrm{R}$ did not have any effect on blue or red litmus.

Substance $\mathrm{S}$ turned China rose indicator green.

$\mathrm{P}, \mathrm{Q}, \mathrm{R}$ and $\mathrm{S}$ could be respectively.

A science teacher has arranged the following sets of test tubes as follows. 

She asked the students to find out the incorrect statement about the above experimental set-up.

Consider the following statements (l-l V) and fill in the blanks by selecting the appropriate option.
I. An antacid such as $\mathrm{P}$ is used to cure indigestion.
II. Lime water contains $\mathrm{Q}$ , which turns milky with carbon dioxide.
III. Soap solution is basic due to the presence of $\mathrm{R}$. It turns the turmeric stain of the shirt to red.
IV. Baking soda is $\mathrm{S}$ which reacts with vinegar to evolve carbon dioxide gas.