Video Transcript
Which of the following is not
correct about potassium hydroxide? (A) Its common name is
limewater. (B) It has the chemical formula
KOH. (C) It turns red litmus paper into
blue. (D) It has a bitter taste. (E) It has a corrosive effect on
the skin.
Potassium hydroxide is a compound
that contains the element potassium and the atomic group hydroxide. Its chemical formula is KOH. Potassium hydroxide is also
commonly known as potash. When potassium hydroxide is added
to water, it dissociates to produce potassium ions and hydroxide ions.
Substances that dissociate in water
to produce negative hydroxide ions are called alkalis. Alkalis are part of a broader class
of substances known as bases. Bases are substances that
neutralize an acid to produce a salt and water. So if potassium hydroxide is an
alkali, it’s also a base.
All bases have similar
characteristics. They have a slippery feel and a
bitter taste. We can test for the presence of a
base using red litmus paper as bases will turn red litmus paper blue. Bases range from weak to strong,
with potassium hydroxide being considered a strong base. In general, the stronger the base,
the more dangerous the base is. Strong bases like potassium
hydroxide tend to be corrosive. This means that the base has high
reactivity that can cause damage to other materials and bodily tissue.
Now that we know some more about
potassium hydroxide, we can determine which of the statements about it is not
correct.
We know that it has the chemical
formula KOH and is corrosive. As these statements are true,
answer choices (B) and (E) cannot be the answer to the question.
Potassium hydroxide is a base, so
it should have a bitter taste and turn red litmus paper blue. So answer choices (C) and (D)
cannot be the answer to the question.
This leaves us with answer choice
(A). We know that the common name of
potassium hydroxide is potash. Limewater is the common name of
calcium hydroxide, a different base.
In conclusion, the statement
regarding potassium hydroxide that is not correct is answer choice (A): its common
name is limewater.
