Question

Abhinav a class 9 student arranged the given setup to study the reactivity of some metals with water .he summerised his observations as follows:

1.In test tube p,there was no reaction in cold water but when th etest tube was heated for a while bubles of gas was seen.
2.In test tube Q,bubbles of gas were formed only after boiling the water .
3.In test tube R,no gas was produced even on boiling the water.
4.In test ube S,reaction occured vigirously.

The metals present in P,Q,R,S could be respectively

A.Na,Mg,Zn,Fe
B.Na,Mg,Al,Cu
C.Mg,Zn,Cu,Na
D.Mg,Zn,Fe,Al

Answer 1

Metals react with water to form a metal hydroxide (or metal oxide) and hydrogen gas. Some metals react with cold water , some with hot water , some with steam and some do not react with steam also.
P = shows no reaction in cold water but reacts only when heated and gas is produced = > Mg
Q = metal reacts only in boiling water and gas is produced ==> Zn
R = metal does not react even with boiling water ==> Cu
S = metal reacts with cold water ==> Na

so the correct option is C ==> Mg, Zn , Cu , Na