Question

which bond is least polar? select the correct answer below: o na - cl o s - cl o p - cl o al - cl

Explanation:

Step1: Recall electronegativity concept

The polarity of a bond depends on the electronegativity difference ($\Delta\chi$) between the two atoms. The smaller the $\Delta\chi$, the less polar the bond.

Step2: Find electronegativity values

Electronegativity of Cl = 3.0. Electronegativity of Na = 0.9, S = 2.5, P = 2.1, Al = 1.6.

Step3: Calculate $\Delta\chi$ for each bond

For Na - Cl: $\Delta\chi=3.0 - 0.9=2.1$.
For S - Cl: $\Delta\chi=3.0 - 2.5 = 0.5$.
For P - Cl: $\Delta\chi=3.0 - 2.1=0.9$.
For Al - Cl: $\Delta\chi=3.0 - 1.6 = 1.4$.

Step4: Compare $\Delta\chi$ values

Since 0.5 (S - Cl) > 0.9 (P - Cl) < 1.4 (Al - Cl)<2.1 (Na - Cl), the P - Cl bond has the smallest electronegativity difference and is the least polar.

Answer:

P - Cl