Answer:
pH of HCl solution is 1.44
Explanation:
NaOH is a monoprotic base and HCl is a monobasic acid.
Neutralization reaction: 
According to balanced reaction, 1 mol of NaOH neutralizes 1 mol of HCl.
Number of moles of NaOH in 13 mL of 0.21 M NaOH
= 
let's assume concentration of HCl is C (M)
Then, number of moles of HCl in 75 mL of C (M) HCl solution
= 
So, we can write, 
or, 
1 mol of HCl contains 1 mol of 
So, concentration of
in 0.0364 M HCl, ![[H^{+}]=0.0364M](https://tex.z-dn.net/?f=%5BH%5E%7B%2B%7D%5D%3D0.0364M)
Hence,