pH of a solution formed by mixing 40 ml of 0.10 M HCL with 10 ml of 0.45 M of NaOH is _____??
Answers
Answer:
Correct option is B)
Solution:- (B) 12
As we know that,
Molarity of a solution =
volume of solution
(in L)
no. of moles of solute
Given:-
Molarity of HCl solution =0.1M
Volume of HCl solution =40mL=0.04L
Therefore,
No. of moles of HCl=0.04×0.1=0.004 mol
Again,
Molarity of NaOH solution =0.45M
Volume of NaOH solution =10mL=0.01L
Therefore,
No. of moles of NaOH=0.01×0.45=0.0045 mol
Now, for the reaction-
NaOH+HCl⟶NaCl+H
2
O
NaOH is in excess.
Therefore,
Excess amount of NaOH=0.0045−0.004=0.0005 mol
Total volume =0.04+0.01=0.05L
Now,Therefore,
Excess amount of NaOH=0.0045−0.004=0.0005 mol
Total volume =0.04+0.01=0.05L
Now,
[OH
−
]=
0.05
0.0005
=0.01M=10
−2
M
Therefore,
pOH=−log[OH
−
]
⇒pOH=−log(10
−2
)=2
Now as we know that,
pH+pOH=14
Therefore,
pH=14−pOH=14−2=12
Hence the pH of the solution is 12.