Question

Calculate the pH value of a solution obtained by mixing 10 ml of 0.1M HCl and 40 ml of 0.2M H2SO4.

Answer 1

H2SO4 dissociates: 
H2SO4 → H+ + HSO4- 
This first dissociation step occurs almost completely which makes H2SO4 a strong acid 

Second step: 
HSO4- → H+ + SO4 2- occurs to a small extent HSO4 - is a weak acid. Its contribution to the [H+] will be small - and even further reduced in the presence of the high [H+] from the HCl. 
HCl is a strong acid that dissociates completely. 

The total [H+] in the final solution is calculated: 
Mol H2SO4 in 40mL of 0.2M solution = 40/1000*0.2 = 0.008 mol H2SO4 
This will dissociate to produce 0.008 mol H+ 
Mol HCl in 10mL of 0.1M solution = 10/1000*0.1 = 0.001 mol HCl 
This will dissociate to produce 0.001 mol H+ 

There is therefore a total of 0.009 mol H+ dissolved in 50mL solution = 0.050L 
Molarity of H+ = 0.009/0.050 = 0.18 M 

pH = -log [H+] 
pH = -log 0.18 
pH = 0.74

Answer 2

Answer:

0.47

here's the answer and hope this helps you.