Q. 1. State the observation for the following reactions:
a. When ammonium dichromate is heated.
b. Addition of lead nitrate to sodium chloride solution.
c. Addition of caustic soda solution to ferric chloride solution.
d. When copper [II] nitrate is heated.
e. Addition of zinc sulphate to sodium hydroxide solution.
f. Hot magnesium metal, added in water and resultant product is checked with red litmus paper
Answers
Answer: (a)(i) Chemical test for ammonia:
If a rod dipped in concentrated hydrochloric acid is brought near ammonia gas, dense white fumes of ammonium chloride (NH4Cl) are formed.
(ii) Chemical test for Sulphur dioxide:
It decolorizes pink coloured potassium permanganate solution.
Selina Solutions Icse Class 10 Chemistry Chapter - Practical Work
(iii) Chemical test for HCl:
When HCl gas is passed through AgNO3 solution, white precipitates of AgCl are formed which gets dissolved in excess of NH4OH.
Selina Solutions Icse Class 10 Chemistry Chapter - Practical Work
(iv) Chemical test for Chlorine:
It turns moist starch iodide paper (KI + starch solution) blue black.
(v) Chemical test for Carbon dioxide:
When this gas is passed through lime water, it turns milky due to the formation of white precipitates of CaCO3 and on passing excess of carbon dioxide gas, this milkiness disappears.
(vi) Chemical test for oxygen:
This gas is absorbed in colourless alkaline solution of pyrogallol and turns it dark brown.
(vii)Chemical test for hydrogen:
It burns with a pop sound when a burning taper is brought near it.
(b)Ammonia is a basic gas and its basic nature is suspected through litmus paper test because it changes the colour of red litmus paper to blue.
(c)Chlorine, carbon dioxide, hydrogen chloride, hydrogen sulphide and sulphur dioxide are acidic gases since they convert blue litmus to red.
(d)A is chlorine and B is Sulphur dioxide.
(e)Water vapour.
Answer:
A sample of ammonium sulphate is warmed with aqueous Sodium
hydroxide the gas produced
a) Ignites with pop b) relishes glowing splint
c) Turns damp red litmus paper to blue d) turns lime water milky
Explanation:
A sample of ammonium sulphate is warmed with aqueous Sodium
hydroxide the gas produced
a) Ignites with pop b) relishes glowing splint
c) Turns damp red litmus paper to blue d) turns lime water milky
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