Is zakat obligatory on an amount of 2000 dirhams deposited in the bank for about a year and a half, given that the exact deposit date is not remembered?

If the money is in an interest-based (riba-based) bank, zakat is obligatory only on the principal amount, and the usurious profits must be disposed of by giving them to the poor or for the general welfare of Muslims. The money must also be withdrawn from this bank.

However, if the money is in an Islamic bank, zakat is obligatory on the entire amount (principal plus profit) if it reaches the nisab (minimum threshold) and a hawl (one lunar year) has passed over it.

To determine the month in which the amount was deposited, one can request a statement from the bank or estimate based on what is most likely. The hawl begins from the time one possesses the nisab, which is the equivalent of 85 grams of gold or 595 grams of silver.