# Question #4221a

Jul 31, 2015

The answer is (2) P with R

#### Explanation:

A neutralization reaction is said to take place when an acid reacts with a base to produce salt and water.

Now, acidic substances have a pH that's lower than 7 and basic substances have a pH that's greater than 7.

A substance that has a pH of 7 is said to be neutral.

So, your substances have the following pH values

$P \to 12.4$
$Q \to 7$
$R \to 1.1$
$S \to 10.3$

Right from the start, substance $Q$ is eliminated because it is neutral. Likewise, a possible reaction between $P$ and $S$ will not be classified as aneutalization reaction because both of these substance are basic, i.e. their pH is greater than 7.

The only option given to you that will produce a neutralization reaction is option (2), in which $P$, a basic substance, reacts with $R$, an acidic substance.

This reaction will result in the production of salt and water.