31. Amongst the metals sodium, calcium, aluminium
iron, copper and magnesium, name the metal :
(i) Which reacts with cold water,
(ii) Which reacts with hot water,
(iii) Which reacts with steam and
(iv) Which does not react even with steam.
Answers
Answer:
(i) Metal which reacts with water only on boiling is Aluminium.
(ii) Metal which does not react even with steam is Copper.
1 =Reactivity series of metals
Order of reactivity Metal Reactions with water or steam
most reactive potassium (K) very vigorous reaction with cold water
Second most reactive sodium (Na) vigorous reaction with cold water
Third most reactive calcium (Ca) less vigorous reaction with cold water
least reactive magnesium (Mg) slow reaction with cold water, vigorous with hot water
2=
That is, Magnesium (Mg) reacts with hot water to form magnesium hydroxide and hydrogen gas. Titanium is normally coated with the oxide layer thus it is inactive. However when exposed to steam forms 7y titanium dioxide, and hydrogenH2.
3=Iron reacts with steam to form iron (II, III) oxide and hydrogen gas.
4=Not only silver does not react even with steam there are also several metals that also do not react with steam. Metal such as lead, copper, and gold do not react with water at all.