What are two likely reasons a Cl ion cannot pass through a sodium ion channel?

The answers are;

1. Cl - is bigger an size atom compared to K+. Therefore, Cl does not fit in the active site of the of the ion channel transmembrane protein.

2. Cl - is an anion while K + is a cation. Cl - therefore does not interact positively with the charges in the channel of the transmembrane protein