Explanation:
Contra entries are passed in the double-column cash book. Let's understand the concept of contra entries and why they are recorded in the double-column cash book.

Contra Entries:
Contra entries refer to transactions where both the cash and bank accounts are involved. In other words, it involves the transfer of funds between the cash account and the bank account. These transactions are commonly known as cash deposits, cash withdrawals, or bank transfers.

Double-Column Cash Book:
The double-column cash book is a type of cash book that has two separate columns for recording cash and bank transactions. One column is used to record cash transactions, and the other column is used to record bank transactions. The cash column is used to record cash receipts and payments, while the bank column is used to record bank deposits and withdrawals.

Reason for Contra Entries in Double-Column Cash Book:
Contra entries involve the transfer of funds between the cash account and the bank account. Since the double-column cash book has separate columns for recording cash and bank transactions, it provides a convenient way to record these types of transactions.

When cash is deposited into the bank, it is recorded in the bank column as a bank deposit and at the same time, the corresponding amount is deducted from the cash column as a cash withdrawal. Similarly, when cash is withdrawn from the bank, it is recorded in the cash column as a cash receipt and at the same time, the corresponding amount is added to the bank column as a bank withdrawal.

This simultaneous recording of cash and bank transactions in the double-column cash book ensures that the cash and bank balances are always in sync.

Conclusion:
In conclusion, contra entries are passed in the double-column cash book because it provides a convenient way to record transactions involving the transfer of funds between the cash account and the bank account. The separate columns for cash and bank transactions in the double-column cash book allow for the simultaneous recording of cash deposits, cash withdrawals, and bank transfers, ensuring that the cash and bank balances are accurately maintained.