Chemistry Hydrogen Important Questions
Q1
(a) Where does hydrogen occurs in free state?
(b) How did the name hydrogen originate ?
Solution :
Q2
Hydrogen can be prepared with the help of cold hydrogen give a reaction of hydrogen with :
(a) a monovalent metal
(b) divalent metal.
Solution :
Q3
Which matter is preferred for preparing hydrogen from:
(a) cold hydrogen
(b) hot hydrogen
(c) steam
Write balance equation for each case.
Solution :
Q4
Hydrogen may be prepared in the laboratory by the action of
a metal with an acid.
(a) Which of the metals copper, zinc, magnesium or sodium
would be the most suitable?
(b) Which of the acids dilute sulphuric, concentrated
sulphuric, dilute nitric and concentrated nitric would you
choose? Explain why you would not use the acids you
rejected.
(c) How would you modify your apparatus to collect dry
hydrogen? Which drying agent would you employ for this
purpose?
Solution :
Q5
Why are the following metals not used in the lab. preparation
of hydrogen?
(a) calcium
(b) iron
(c) aluminium
(d) sodium
Solution :
Q6 Based on the reactions of hydrogen on metals, arrange the following metals in increasing order of reactivity: Iron, sodium, magnesium, zinc, calcium.
Solution :
Q7 Hydrogen is evolved when dilute HCI reacts with magnesium, but nothing happens in the case of mercury and silver. Explain.
Solution :
Q8 Steam can react with a metal and a non-metal to liberate hydrogen. Give the necessary conditions and equations for the same.
Solution :
Q9
Hydrogen is obtained by displacement from
(a) dilute sulphuric acid
(b) dilute hydrochloric acid
Write equations using zinc and iron.
Why does not copper show similar behaviour?
Solution :
Q10
Give a reason for the following
(a) Though lead is above hydrogen in the activity series, it is
not used to prepare hydrogen.
(b) Potassium and sodium are not used for reaction with
dilute hydrochloric acid or dilute sulphuric acid in the
laboratory preparation of hydrogen.
Solution :
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