Final answer:
Countries put limitations on the convertibility of their currencies to prevent a sudden outflow of foreign capital, which could lead to a decline in their currency and potentially collapse their banking system.
Step-by-step explanation:
When countries are concerned that their foreign reserves could be depleted, they may put limitations on the convertibility of their currencies. This is often done to prevent a sudden outflow of foreign capital, which could lead to a decline in their currency and potentially collapse their banking system. One example of such limitations is the imposition of capital controls, which restrict the flow of money across borders. These controls can take various forms, such as limiting the amount of currency that can be exchanged or imposing taxes or fees on foreign exchange transactions.