Which compound contains both ionic and covalent bonds?

(1) ammonia

(2) methane

(3) sodium nitrate

(4) potassium chloride

The answer is (3) sodium nitrate. Sodium nitrate is NaNO3. The bond between N and O ion is covalent bond and the bond between Na + and NO3 - is ionic bond.

Answer is (3) - Sodium Nitrate.

Normally ionic bonds can be seen between metals and non-metals while covalent bonds present between non-metals. Another thing that determines the bond nature is electronegativity value of the atoms. If the electronegativity difference is high, then that bond tends to be an ionic bond.

Sodium nitrate consists of Na⁺ and NO₃⁻ ions. Hence, the bond between Na⁺ and NO₃⁻ is an ionic bond.

NO ₃⁻ is made from N and O. Both are non-metallic atoms. The electronegativities of N and O are 3.0 and 3.5 respectively. Hence, there is no big difference between electronegativity values (3.5 - 3.0 = 0.5). Hence, the bond between N and O is a covalent bond.