Question

question 4 of 25
which of the following is a binary compound?
a. cao
b. nh₄⁺
c. o²⁻
d. h₂so₄

Explanation:

A binary compound is a compound composed of two different elements. Let's analyze each option:

• Option A: $\ce{CaO}$ is composed of calcium (Ca) and oxygen (O), two different elements, so it is a binary compound.
• Option B: $\ce{NH_4^+}$ is a polyatomic ion (ammonium ion), not a compound (it's an ion, and also composed of nitrogen and hydrogen, but it's an ion, not a neutral compound in the context of binary compounds here).
• Option C: $\ce{O^{2-}}$ is an oxide ion, a single ion, not a compound.
• Option D: $\ce{H_2SO_4}$ (sulfuric acid) is composed of hydrogen, sulfur, and oxygen (three elements), so it's a ternary compound, not binary.

Answer:

A. $\ce{CaO}$