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Practical Chemistry Dalal Simplified ICSE Class-9 Solutions

Chapter-9 Practical Chemistry by Dr Viraf J Dalal Middle School Chemistry Allied Publishers

Practical Chemistry Dalal Simplified ICSE Class-9 Solutions Chapter-9. We Provide Step by Step Answer of Exercise /Lesson -9 Practical Chemistry with Additional Questions , Previous Year Questions and Unit Test-9 of Dr Viraf J Dalal Middle School Chemistry Allied Publishers New Simplified Chemistry . Visit official Website CISCE for detail information about ICSE Board Class-9.

Practical Chemistry Dalal Simplified ICSE Class-9 Solutions Chapter-9


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Previous Year Questions

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Additional Questions

Unit Test-9


ADDITIONAL QUESTIONS Practical Chemistry Dalal Simplified

Question 1.


Give a chemical test to distinguish between the following gases:
(a) Hydrogen and oxygen
(b)Carbon dioxide and sulphur dioxide
(c) Hydrogen chloride and hydrogen sulphide
(d) Chlorine and nitrogen dioxide
(e) Ammonia and hydrogen chloride
(f) Sulphur dioxide and chlorine.
Answer:
Chemical test to distinguish between
(a)
Hydrogen:
 Bums with a pale-blue flame when a burning splint is brought near it. Oxygen : The gas turns an alkaline solution of pyrogallol dark brown.
(b)
Carbon dioxide [CO2]:
 Pass the gas through acidified potassium permanganate solution pink colour does not change.
Sulphur dioxide [SO2]: Potassium permanganate sol. pink colour changes to clear colourless.

(c)
Hydrogen chloride [HCl]: Turns silver nitrate sol. into curdy white ppt. This ppt. is soluble in NH4OH but insoluble in dil. HN03 does not show lead acetate paper test.
Hydrogen sulphide [H2S]: Shows no such test, with AgNO3[sol.] Put moist lead acetate paper in H2S gas. It turns silvery black.

(d)

Chlorine [Cl2]:

  1. Moist litmus [blue] turns red and gets bleached,
  2. Turns moist starch iodide paper blue black.

Nitrogen dioxide [NO2]:

  1. Turns blue litmus red.
  2. Displaces I2 from KI and turns potassium iodide paper brown.

(e)
Ammonia [NH3]:
 Bring a glass rod dipped in cone. HCl gives dense white fumes. Turns nessler’s reagent from colourless to pale-brown.
Hydrogen chloride [HCl]: Bring a glass rod dipped in cone. HCl, no white fumes. No-action with nessler’s reagent.

(f)
Sulphur dioxide [SO2]:

  1. Moist blue litmus paper turns red.
  2. turns acidified potassium permanganate from pink to colourless.

Chlorine [Cl2]:

  1. Moist blue paper turns red and gets bleached
  2. Turns moist starch iodide paper blue-black

Question 2.


On heating which of the following substances i.e. copper carbonate, zinc carbonate, washing soda, copper sulphate, zinc nitrate, copper nitrate, lead nitrate, ammonium chloride and ammonium dichromate – relate to the reactions given below.


(a) A white substance which leaves an amphoteric oxide as a residue [whose colour varies in the heated and in the cold state] and evolves a gas which turns lime water milky.
(b) An efflorescent substance which leaves a residue having the same colour as the substance and evolves a gas which changes the colour of cobalt chloride paper.
(c) A white solid which evolves two colourless gases which on cooling combine and condense on the cooler parts of the test tube.

(d) A coloured substance which decomposes violently leaving a coloured residue and evolving two neutral gases one of which is unreactive or inert in nature.
(e) A coloured substance which leaves a black residue and evolves two gases one of which is acidic and coloured and the other neutral and colourless.

(f) A coloured substance which leaves on strong heating a black residue and evolves two colourless gases one of which is acidic and the other neutral.
(g) A white crystalline solid which decrepitates on heating leaving a residue which fuses with the glass and evolves two gases one of which is coloured and acidic.
(h) An amorphous substance which turns from pale green to black on strong heating evolving a colourless, acidic gas as the only gaseous product.
Answer:

(a) Zinc carbonate [ZnCO3].
(b) Washing soda Na2CO3.10H2O Efflorescent substance.
(c) Ammonium chloride [NH4Cl].
(d) Ammonium dichromate [orange] [NH] Cr2Or
(e) Copper nitrate Cu[NO3]2.
(f) Copper sulphate [CuSOJ.
(g) lead nitrate Pb[NO3]2.
(h) Copper carbonate CuCO3.

Question 3.


Give balanced equations for the following conversions affected by heat alone on the substances:
(a) Copper carbonate to copper oxide;
(b) Hydrated copper sulphate to sulphur dioxide;
(c) Copper nitrate to nitrogen dioxide;
(d) Ammonium dichromate to nitrogen; .
(e) Zinc carbonate to zinc oxide;
(f) Zinc nitrate to nitrogen dioxide
Answer:

Action of heat on:
(a)

 

Ans 2 Practical Chemistry Dalal Simplified Class-9 ICSE

Question 4.


Using dilute sulphuric acid how would you differentiate between:
(a) Copper and magnesium.
(b) Sodium sulphide and sodium carbonate.
How would you identify the gaseous products evolved.
Answer:


Action of dil. H2SO4 on
(a) Copper — has no action
Magnesium — produces H2 burns with blue flame with pop-sound.
(b) Sodium sulphide → H2S
Na2S + H2SO4→ Na2S04 + H2 S→Turns lead acetate paper silvery black
Sodium carbonate → C02
Na CO + H9S04 → Na2SO4 + H20 + CO2
CO2 — Turns lime water milky.

Question 5.


Using a platinum wire, cone, hydrochloric acid and a Bunsen burner how would you distinguish between the three salts e. sodium chloride, potassium chloride and calcium chloride. Explain in brief the method used for the same.

Answer:


Application of flame test – to identify the metal in the substance

Ans 5 Practical Chemistry Dalal Simplified Class-9 ICSE

Question 6.


Using given samples of temporary and permanent hard water, soft water, ordinary soap, detergent and washing soda how would you

(a) distinguish between hard and soft water
(b) distinguish between temporary hard water and permanent hard water
(c) remove temporary hardness from water without using a chemical compound
(d) remove temporary hardness and permanent hardness from water using a chemical compound
(e) prove the advantage of detergent over soap.
Answer:


(a) Differentiating hard water from soft water
  1. Two unknown samples ‘X’ and ‘Y’ containing hard water and soft water are taken – separately in the trough or beaker.
  2. Ordinary soap is rubbed by the hands – inside each sample.

Observation

  1. One sample of water ‘X’ lathers with soap.
  2. The sample of water ‘Y’ does not lather with

Result

  1. Sample ‘X’ which lathers is – soft water.
  2. Sample ‘Y’ which does not lather is – hard
(b) Differentiating temporary and permanent hard water
  1. Two unknown samples ‘A’ and ‘B’ containing temporary and permanent hard water are taken – separately in a trough or beaker.
  2. The water is boiled slowly, gases allowed to escape out, and then the water is filtered.
  3. Ordinary soap is rubbed by the hands – inside each filtered sample.

Observation

  1. One sample of water ‘A’ – lathers with soap.
  2. The sample of water ‘B’ – does not lather with

Result

  1. The boiled and filtered sample ‘A’ which lathers is temporary hard water – whose hardness is removed by boiling. Sample ‘B’ is permanent hard water – whose hardness cannot be removed by boiling.

(c) Remove temporary hardness from water without using chemical compound. Temporary hardness can be removed by heating the hard water.

Experiment


Temporary hard water softened by heating

  1. Temporary hard water is taken in a beaker and heated
  2. After the gases escape out, the water is filtered through a filter paper.
  3. Ordinary soap is rubbed – inside the filtered solution.

Observation

  1. The boiled and filtered sample of – temporary hard water lathers readily with soap.

Result

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