Page 245 - Chemistry ICSE Class X

Study of Compounds–Ammonia 231
ƒ Water vapour condense at the end of the combustion tube or in the
delivery tube.
ƒ Nitric oxide gas [NO(g ? KU EQNNGEVGF KP VJG ƀCUM %QNQWTNGUU 01 g)
turns brown due to the formation of NO (g) by the reaction between
2
NO(g) and O (g KP VJG ƀCUM
2
2NO(g) + O (g) o 2NO (g)
2
2
nitric oxide from air nitrogen dioxide
(reddish brown)
The catalytic oxidation of ammonia resulting in the formation of
nitric oxide forms the basis of Ostwald process for the manufacture of
nitric acid.

What are the uses of ammonia
The following are the main uses of ammonia:
ƒ In ice-plants and refrigeration. #OOQPKC ECP DG GCUKN[ NKSWGſGF CPF ŵŵŽŶŝĂ ŝƐ ƚŚĞ ŵŽƐƚ ĞŶǀŝƌŽŶŵĞŶƚͲ
liquid ammonia has a high heat of vaporisation. This makes ammonia ĨƌŝĞŶĚůLJ ŶĂƚƵƌĂů ƌĞĨƌŝŐĞƌĂŶƚ͘
quite useful as a refrigerant in refrigerators, cold storage and ice- /ƚ ŚĂƐ ŽnjŽŶĞ ĚĞƉůĞƟŽŶ ƉŽƚĞŶƟĂů
making plants. ĞƋƵĂů ƚŽ njĞƌŽ͘
ƒ Ammonia solution for domestic purpose. Dilute solution of ammonia
in water is known as ‘domestic ammonia’ or ‘household ammonia’, is
used as a cleansing agent.
ƒ For manufacturing urea. Ammonia is used industrially for the
manufacture of urea which is an important fertilizer.
ƒ (QT OCPWHCEVWTKPI CTVKſEKCN UKNM Ammonia is used in the manufacture
QH CTVKſEKCN UKNM TC[QP ŵŵŽŶŝƵŵ ĐŚůŽƌŝĚĞ ŝƐ ƵƐĞĚ ŝŶ ĚƌLJ
ĐĞůůƐ͘
ƒ For manufacturing nitric acid. Ammonia is used in the manufacture
of nitric acid by the Ostwald’s process.
ƒ For manufacturing sodium carbonate. Sodium carbonate is
manufactured from ammonia by the Solvay’s process.
ƒ For making ammonium compounds. Large amount of ammonia is
used for making many ammonium compounds.
ƒ As a source of hydrogen: ŵŵŽŶŝƵŵ ŶŝƚƌĂƚĞ ŝƐ ƵƐĞĚ ĂƐ Ă
ĐŽŵƉŽŶĞŶƚ ŽĨ ĞdžƉůŽƐŝǀĞ ŵŝdžƚƵƌĞƐ
RuO /J-Al O
2NH (g) o N 2 + 3H 2 ƵƐĞĚ ĨŽƌ ŵŝŶŝŶŐ ĂŶĚ Đŝǀŝů ĐŽŶƐƚƌƵĐƟŽŶ
2
2
3
3
ammonia clean energy source ƉƵƌƉŽƐĞƐ͘
(in fuel cells)
What are the tests of ammonia
6JG RTGUGPEG QH COOQPKC KP CP[ UCORNG OC[ DG EQPſTOGF D[ VJG HQNNQYKPI
tests:
ƒ Odour. Ammonia has a characteristic pungent smell (called
ammoniacal smell).
ƒ Action on litmus. Ammonia turns moist red litmus blue, and moist
turmeric paper brown.
ƒ With copper sulphate solution. Ammonia when added to a solution
of copper sulphate, turns the solution deep blue.
ƒ With HCl. When a glass rod dipped in conc. HCl is brought closer to
ammonia, dense white fumes are observed.
ƒ With Nessler’s reagent. Ammonia when added to Nessler’s reagent
(alkaline solution of K [HgI ]) gives brown precipitate.
4
2