Question

U. Amphoteric Behavior of Aluminum Hydroxide B. Test for basic behavior. Describe what happened when HCl was added. # dissolved C. Test for acidic behavior. Describe what happened when NaOH was added. Dident dissole i continued to precipitate. 1. QUESTIONS: Which metals are more reactive - alkali metals (Group IA) or alkaline earth metals (Group ILA)? How do you know? 2. Based on your observations regarding Group IIA metals (calcium and magnesium), which Group IIA metal would you expect to react more rapidly with water beryllium or barium? Why? 3. Write balanced chemical equations for each of the following. In this part, first write the names of the products on the right hand side of the first line; then write the balanced chemical equation on the line underneath. a. Lithium + water - b. Sodium + nitric acid → c. Aluminum + sulfur - (Continued on the next page) - 75 -

Answer 1

1) Alkali metals are more reactive than alkaline earth metals because of their low Ionization enthalpy and large size. Since alkali metals loses electron easliy to attain noble gas configuration hence they have low Ionization enthalpy.

2) Barium react rapidly with water whereas Beryllium not react with water. Due to small size of Beryllium and it's high ionization enthalpy it is less reactive.

3) a) Lithium + water -> lithium hydroxide + hydrogen gas

Li(s) + H2O(l) -> LiOH(aq) + 1/2H2(g)

b) Sodium + nitric acid -> sorium nitrate + hydrogen gas

Na(s) + HNO3(aq) -> NaNO3(aq) + 1/2H2(g)

c) Aluminum + sulphur -> aluminum sulphide

16Al(s) + 3S8(s) -> 8Al2S3 (s)

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