柯林斯词典alkali /ˈælkəˌlaɪ/ (alkalis) 1. N-MASS An alkali is a substance with a pH value of more than 7. Alkalis form chemical salts when they are combined with acids. 碱 返回 alkali剑桥词典a substance that has the opposite effect or chemical behaviour to an acid 碱；强碱 返回 alkali