Question

Assertion (A): Balloons made by nylon films are better for containing helium than the conventional rubber balloons.
Reason (R): R.M.S. The velocity of helium is very high. So, helium atoms can effuse out through rubber balloons.
(a) Both A and R are correct and R is the correct explanation of A.
(b) Both A and R are correct and R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.

Answer 1

Helium is a chemical element having a formula $He$ and it is a colourless, odourless, inert and a monatomic gas. It is used in the party balloons and shield for arc welding and pressurizing the fuel tanks.

Complete step by step answer:
First of all we analyse the assertion and reasons are correct or not and then if the reason is the correct explanation of the assertion or not.
Starting with the assertion:
Assertion states that the Balloons made by nylon films are better for containing helium than the conventional rubber balloons. This statement is true that the balloons are made up of the nylon films because of the high R.M.S. velocity of the helium atoms, they effuse out of the rubber balloons. So, the nylon films are used in the place of conventional rubber balloons.
Now, moving forward to the Reasons:
Reason states that R.M.S. The velocity of helium is very high. So, the helium atoms can effuse out through rubber balloons. The R.M.S. The velocity of the helium is actually very high because the R.M.S. velocity of an atom is inversely proportional to the square root of molecular mass of the molecule or atomic mass of the atom. So, the reason is also a true and correct explanation for the assertion.
So, the assertion and reason both are correct and also reason is the correct explanation of assertion.
Hence, the correct option is (a) Both A and R are correct and R is the correct explanation of A.

Note:
R.M.S. velocity stands for root mean square velocity of the atom. The velocity is directly proportional to the square root of temperature and Gas constant and inversely proportional to the square root of the molecular mass of the molecule or atomic mass of the atom (The elemental form or molecular form in which the molecule exists. For example, for the oxygen, molecular mass will be sixteen and for the helium, mass will be four).