0.73 M is the concentration of sulfuric acid that needed 47 mL of 0.39M potassium hydroxide solution to neutralize a 25 mL sample of the sulfuric acid solution.
Explanation:
Data given:
Volume of the base = 47 ml
molarity of the base= 0.39 M
volume of the acid = 25 ml
molarity of the acid =?
For titration reaction between acid and base, the volume or molarity of any of the base or acid can be determined. The formula used:
Macid X Vacid = Vbase x Mbase
Macid = 
putting the values given in the rearranged equation above:
Macid = 
= 0.73 M
The concentration of the sulphuric acid needed is 0.73 M.
Acid is an substance that ionized in water to produce hydrogen ion
Atom is the smallest neutral particle in the element
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.