Which of the following metals react with water? (Hint: Look at the activity series). 1. Au; 2. Li; 3. Hg; 4. Ca; 5. Pt

Answer

To determine which metals react with water, we must refer to the metal activity series. The activity series ranks metals from most reactive to least reactive. Metals at the very top of the series (alkali and some alkaline earth metals) are reactive enough to react with cold water to produce metal hydroxides and hydrogen gas. Based on the options provided: 1. Lithium (Li) is an alkali metal located near the top of the activity series and reacts vigorously with water. 2. Calcium (Ca) is an alkaline earth metal also located high on the activity series and reacts readily with water. 3. Gold (Au), Mercury (Hg), and Platinum (Pt) are located at the bottom of the activity series; they are chemically inert and do not react with water. Therefore, the metals that react with water among the list are Lithium (2) and Calcium (4). The correct answer choice is '2 and 4'.