chemistry

HYDROGEN 

One mark question:

1.     What is meant by 10 volume hydrogen peroxide?

2.     Why is dihydrogen gas not preferred in balloons?

3.     Name the constituents of water gas.

4.     Name one compound each in which hydrogen exists in (i) positive oxidation state, and (ii) Negative oxidation state.

5.     What type of elements form interstitial hydrides?

6.     How many hydrogen bonded water molecule(s) are present in CuSO₄.5H₂O?

7.     What happens when heavy water is added to calcium carbonate?

8.     Concentrated sulphuric acid cannot be used for drying H₂. Why?

9.     Complete the following reactions?

(i)        C₃H₈ (g)  +  3H₂O(

(ii)      Zn(s)  +  NaOH(aq)

10. How heavy water is is obtained from ordinary water?

Solutions:

1.     It means that 1 ml of H₂O₂will give 10 ml of oxygen at N.T.P.

2.     Dihydrogen gas is combustible in nature. Therefore, it may react with oxygen highly violently. Thus, it is not used in balloons.

3.     Carbon monoxide and hydrogen.

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4.     (i) HCl (ii) NaH

5.     Elements of d-and f-block.

6.     In CuSO₄.5H₂O, there is one hydrogen bonded water molecule which is outside the coordination sphere. The other four molecules of water are coordinated.

7.     Deutero acetylene is formed.

	CaC2	+  2D2O	Ca(OD)2			+  C2D 2
8.	Conc. H2SO4 on absorbing water from moist H2 produces so much heat that H2
	catches fire.
9.
	(i)	C3H8 (g)  +  3H2O(					3CO  +  7H2(g)
	(ii)	Zn(s)  +  NaOH(aq)					Na2ZnO2(aq)  +  H2(g)

10. Heavy water is obtained from ordinary water by repeated electrolysis in the presence of 3% NaOH.