look at the chemical tables. but i believe it is A
Solution us here,
let the rate of diffusion of H2(r1) be x and⁷ the rate of diffusion of gas(r2) be x+x/6=7x/6.
Molar mass of H2 (M1)=2 g
Molar mass of gas(M2)= ?
Now, from the Ghram's law of diffusion of gas,

here, it looks like I have done wrong.
But all of the answers in option are wrong.
Because, rate of diffusion of any gas is inversely proportional to the square root of its malor mass.
And in the question, gas has higher rate of diffusion than hrdrogen. So it should have molar mass less than hydrogen.
Calcium is Ca, Carbon is C, Chlorine is Cl
The answer is C
Answer:
It measures the capacity to do work.
Explanation: