Britain used opium as a trade product to meet the demand for what?

In 1842, the treaty of nanking—the first of what the chinese later called the unequal treaties—granted an indemnity and extraterritoriality to britain, the opening of five treaty ports, and the cession of hong kong island. the failure of the treaty to satisfy british goals of improved trade and diplomatic relations led to the second opium war (1856–60). in china, the war is considered the beginning of modern chinese history.