The balanced equation between the
and
is:

Formula of molarity is:


Substituting the values,

So, number of moles of
is
.
From the balanced equation it is clear that for 1 mole of
, 2 moles of
are required.
Hence, 0.21 mole of
= 
Molar mass of
= 
So, the mass of
= 
Answer:
λ = 1×10²⁶m
Explanation:
Given data:
Wavelength of radiation = ?
Frequency of radiation = 3×10⁻¹⁸Hz
Solution:
Formula:
c = f × λ
c = speed of wave = 3×10⁸ m/s
by putting values,
3×10⁸ m/s = 3×10⁻¹⁸Hz × λ
λ = 3×10⁸ m/s / 3×10⁻¹⁸s⁻¹
λ = 1×10²⁶m
It would likely be HF. It displays hydrogen bonding.