Question

NaOH was adde to a 7.75 x 10^-3 M solution of HCl so that the end solution has a pH of 3.500. What is the positive difference in concentration of [H3O+]

Answer 1

Answer:

concentration [H_3O^+][H3O+] decreased by 4.46334\sdot10^{-4}M.4.46334⋅10−4M.

Explanation:

pH=−log[H3O+]; [H_3O^+]=10^{-pH};[H3O+]=10−pH;

If pH=3.350;pH=3.350;

[H_3O^+]=10^{-3.35}=4.467\sdot10^{-4}M;[H3O+]=10−3.35=4.467⋅10−4M;

If pH=6.780;pH=6.780;

[H_3O^+]=10^{-6.78}=1.66\sdot10^{-7}M;[H3O+]=10−6.78=1.66⋅10−7M;

4.467\sdot10^{-4}-1.66\sdot10^{-7}=4467\sdot10^{-7}-1.66\sdot10^{-7}=4465.34\sdot10^{-7}=4.467⋅10−4−1.66⋅10−7=4467⋅10−7−1.66⋅10−7=4465.34⋅10−7=

=4.46534\sdot10^{-4}M;=4.46534⋅10−4M;

Answer 2

The positive difference in concentration of [$H_3O^+$] is $4.46534 X 10^{-4}M$ when NaOH was added to a 7.75 x $10^-3$ M solution of HCl so that the end solution has a pH of 3.500.

What is concentration?

It is the measure of how much of a given substance there is mixed with another substance.

pH=−log[$H_3O^+$]

[$H_3O^+$]=$10^{-pH}$

[$H_3O^+$]=$10^-^p^H$

If pH=3.350

pH=3.350

[$H_3O^+$]=$10^{-3.35}$=$4.467 X 10^{-4}M$

[$H_3O^+$]=$10^{-3.35}$

=$4.467 X 10^{-4}M$

If pH=6.780

pH=6.780

[$H_3O^+$]= $10^{-6.78}$=$1.66 X 10^{-7}M$

Hence, the positive difference in concentration of [$H_3O^+$] is$= 4.46534 X 10^{-4}M$

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