The list shows three substances and their chemical natures.
Substance Chemical Nature
milk of magnesia basic
distilled water neutral
lemon juice acidic
Which of the following correctly lists the substances from highest to lowest pH?
A.
lemon juice, distilled water, milk of magnesia
B.
distilled water, milk of magnesia, lemon juice
C.
lemon juice, milk of magnesia, distilled water
D.
milk of magnesia, distilled water, lemon juice
C. lemon juice, milk of magnesia, distilled water
The correct answer is option C: lemon juice, milk of magnesia, distilled water.
To determine the correct order of substances from highest to lowest pH, you need to understand the concept of acidity and alkalinity. The pH scale ranges from 0 to 14, with values less than 7 considered acidic, 7 considered neutral, and values greater than 7 considered basic or alkaline.
From the given list, we know that milk of magnesia is basic, distilled water is neutral, and lemon juice is acidic.
To decide which substance has the highest pH, we need to look at their chemical natures. Milk of magnesia is basic, which means it will have a pH greater than 7. Distilled water is neutral, with a pH of exactly 7. Lemon juice is acidic, with a pH less than 7.
Looking at the options provided:
A. lemon juice, distilled water, milk of magnesia - This option is in the correct order, with lemon juice being the most acidic, followed by distilled water, and then milk of magnesia, making it the correct answer.
B. distilled water, milk of magnesia, lemon juice - This option is in the reverse order, so it's not correct.
C. lemon juice, milk of magnesia, distilled water - This option is also in reverse order, so it is not correct.
D. milk of magnesia, distilled water, lemon juice - This option is in the reverse order, so it is not correct.
Therefore, the correct answer is option A:
lemon juice, distilled water, milk of magnesia.