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The equation for the pH of a substance is pH = –log[H+], where H+ is the concentration of hydrogen ions. A basic solution has a pH of 11.2. An acidic solution has a pH of 2.4. What is the approximate difference in the concentration of hydrogen ions between the two solutions? a) 1.6*10^-9 b) 4.0*10^-3 c)6.7*10^-1 D)1.6*10^-1

2 Answers

5 votes
PH=-log[H⁺]

First solution:
PH=11.2

11.2=-log[H⁺]

log[H⁺]=-11.2
[H⁺]=10⁻¹¹.²=6.0309⁻¹²


Second solution:
PH=2.4

2.4=-log[H⁺]
log[H⁺]=-2.4
[H⁺]=10⁻².⁴=3.98*10⁻³

Difference between the two solutions=3.98*10⁻³ - 6.03*10⁻¹²≈4.0*10⁻³.

Answer: b) 4.0*10⁻³
User Terco
by
8.1k points
2 votes

Answer:

The correct answer si option (b).

Step-by-step explanation:


pH = -\log[H+]

Concentration of hydrogen ions when pH is 11.2.


11.2=-\log[H^+]


[H^+]=6.309* 10^(-12) M

Concentration of hydrogen ions when pH is 12.4.


2.4=-\log[H^+]


[H^+]'=0.0039810 M=3.9810* 10^(-3) M

Difference between the hydrogen ions:


=[H^+]'-[H^+]


=0.00398 M-6.309* 10^(-12) M=0.00397 M=3.97* 10^(-3)\approx 4.0* 10^(-3)M

Hence, the correct answer si option (b).

User Jfcartier
by
7.9k points

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