Answer:To calculate the pH of a hydrochloric acid (HCl) solution, you need to know that HCl is a strong acid and fully dissociates in water. This means the concentration of hydrogen ions
[
+
]
[H
+
] in the solution is equal to the concentration of HCl.
Explanation:Given the concentration of HCl is
3.5
×
1
0
−
5
M
3.5×10
−5
M:
[
+
]
=
3.5
×
1
0
−
5
M
[H
+
]=3.5×10
−5
M
The pH is calculated using the formula:
pH
=
−
log
[
+
]
pH=−log[H
+
]
Now, let's calculate it:
pH
=
−
log
(
3.5
×
1
0
−
5
)
pH=−log(3.5×10
−5
)
To perform this calculation, we can break it into two parts:
Calculate the logarithm of the base 10 of
3.5
3.5.
Adjust for the exponent
−
5
−5.
First, use the properties of logarithms:
log
(
3.5
×
1
0
−
5
)
=
log
(
3.5
)
+
log
(
1
0
−
5
)
log(3.5×10
−5
)=log(3.5)+log(10
−5
)
Since
log
(
1
0
−
5
)
=
−
5
log(10
−5
)=−5:
log
(
3.5
×
1
0
−
5
)
=
log
(
3.5
)
+
(
−
5
)
log(3.5×10
−5
)=log(3.5)+(−5)
The value of
log
(
3.5
)
log(3.5) is approximately
0.544
0.544:
log
(
3.5
×
1
0
−
5
)
=
0.544
−
5
=
−
4.456
log(3.5×10
−5
)=0.544−5=−4.456
Now, take the negative of this value to find the pH:
pH
=
−
(
−
4.456
)
=
4.456
pH=−(−4.456)=4.456
Therefore, the pH of a
3.5
×
1
0
−
5
M
3.5×10
−5
M HCl solution is approximately
4.456
4.456.