Final answer:
In the 19th century, Europe had to use silver in trade with China because it was the only form of payment that China accepted for their goods.
Step-by-step explanation:
In the 19th century, Europe had to use silver in trade with China because it was the only form of payment that China accepted for their goods. China had a self-sufficient economy and was uninterested in Western products, so the only way to balance the trade deficit was by using silver. Chinese teas, jade, silks, and porcelain were highly sought after in the West, and the silver from the New World became the main currency in China's economy.