chloride(out) + Na(+)(out) = chloride(in) + Na(+)(in)
chloride(out) + na(+)(out) = chloride(in) + na(+)(in)
chloride(out) + Na(+)(out) = chloride(in) + Na(+)(in)
chloride(out) + na(+)(out) = chloride(in) + na(+)(in)