Is Zakat obligatory if the gold does not reach the nisab (minimum taxable amount) and the money does not reach the nisab of silver, but selling the gold would lead to possessing the nisab of silver or more?

Zakat is obligatory on cash and gold if their combined value reaches the nisab (threshold) of gold, or if the cash alone reaches the nisab of gold. However, if the cash does not reach the nisab of gold, but together with the gold it reaches the nisab of silver, then zakat is also obligatory on them. This is the view of the majority of scholars. If neither the cash nor the gold, even when combined, reach any nisab, then no zakat is due on them.