Which compound in the given pairs would undergo an S_N2 reaction more rapidly?

Comparison of two compounds with Br and Cl for SN2 reaction analysis.

Illustration of two compounds with Br and Cl for SN2 reaction comparison.

Visual comparison of two compounds featuring Br and Cl for SN2 reaction speed.

Diagram showing two compounds with Br and Cl for SN2 reaction evaluation.

Which compound in the given pairs would undergo an SN2 reaction more rapidly?