Select the correct answer from A, B, C and D : The aim of the Fountain experiment is to prove that :

(A) HCl turns blue litmus red

(B) HCl is denser than air

(C) HCl is highly soluble in water

(D) HCl fumes in moist air.

HCl dissolves in toluene (C₆H₅CH₃) and the solution:

P — contains hydronium ions.

Q — can produce carbon dioxide on reacting with sodium carbonate.

R — does not show any acidic property.

Which of the following holds true?

1. Only P
2. Only Q
3. Only R
4. Both P and Q

Assertion (A): The Fountain experiment is used to demonstrate the high solubility of HCl gas.

Reason (R): Red litmus solution turns blue in Fountain experiment.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Assertion (A): HCl gas is collected by downward delivery.

Reason (R): HCl gas is heavier than air.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.