Which of the following is a Lewis base? This question often arises in chemistry, particularly when discussing acid-base reactions and the concept of electron pair donation. In this article, we will explore the characteristics of a Lewis base and identify which of the given options qualifies as one.
A Lewis base is defined as a substance that can donate a pair of electrons to form a coordinate covalent bond with an electron-deficient species, known as a Lewis acid. This concept was introduced by Gilbert N. Lewis in 1923 and has since become a fundamental principle in understanding chemical bonding and reactivity.
To determine which of the following is a Lewis base, we must consider the ability of each option to donate a pair of electrons. Let’s examine the given options:
1. HCl (hydrochloric acid)
2. H2O (water)
3. NH3 (ammonia)
4. CH4 (methane)
HCl is a strong acid and typically does not act as a Lewis base. Instead, it accepts a pair of electrons to form a bond with a Lewis base. Therefore, HCl is not the correct answer to the question “Which of the following is a Lewis base?”
Water (H2O) is a polar molecule with two lone pairs of electrons on the oxygen atom. This makes it capable of donating a pair of electrons to a Lewis acid, qualifying it as a Lewis base. Thus, H2O is a valid answer to the question.
Ammonia (NH3) is another example of a Lewis base. It has a lone pair of electrons on the nitrogen atom, which can be donated to a Lewis acid. Therefore, NH3 is also a correct answer to the question.
Methane (CH4) is a nonpolar molecule with no lone pairs of electrons on the carbon atom. As a result, it cannot donate a pair of electrons to a Lewis acid and is not a Lewis base.
In conclusion, the correct answers to the question “Which of the following is a Lewis base?” are H2O (water) and NH3 (ammonia). These substances possess the necessary electron pair donation capabilities that define a Lewis base in chemical reactions.
