FRANK Solutions for Class 10 Chemistry Chapter 4 - Analytical Chemistry

Chapter 4 - Analytical Chemistry Exercise 85

Question 1

Write the colour of the following salts:
(a) Cuprous salts.
(b) Cupric salts.
(c) Aluminium salts.
(d) Ferrous salts.
(e) Ferric salts.
(f) Calcium salts.

Solution 1

(a) Cuprous salts = Colourless
(b) Cupric salts = Blue
(c) Aluminium salts = Colourless
(d) Ferrous salts= Light green
(e) Ferric salts = Yellow
(f) Calcium salts = Colourless

Question 2

Using ammonium hydroxide, how would you distinguish between the following pairs of ions in solution?
(a) Ferrous ion and Ferric ion.
(b) Zinc ion and Lead ion.

Solution 2

Question 3

You are provided with PbCO₃, ZnCO₃ and CaCO₃. How will you identify these cations?

Solution 3

Question 4

Z is a compound. With dilute HCl it gives a gas turning dichromatic solution green. Z gives lilac flame. Name Z.

Solution 4

K₂SO₄.

Question 5

What do you observe when caustic soda solution is added to the following solution: first a little and then in excess
(a) FeCl₃
(b) ZnSO₄
(c) Pb(NO₃)₂
(d) CuSO₄

Solution 5

Question 6

What is the reaction of freshly precipitated aluminium hydroxide with caustic soda solution? Give equation.

Solution 6

Question 7

What do you understand by amphoteric oxide? Give the balanced equations for the reaction with three different amphoteric oxides with a caustic alkali. Write your observation if any.

Solution 7

Question 8

Name a solution that will separate the components of the following mixtures:
(a) Zn(OH)₂ from Pb(OH)₂
(b) CaO from PbO
(c) CuO from ZnO

Solution 8

Question 9

Give two examples of amphoteric hydroxides.

Solution 9

Examples of amphoteric hydroxides are: Zn(OH)₂, Al(OH)₃.

Question 10

A metal whose alloy finds use in the construction of aircrafts in the powdered form is added to sodium hydroxide solution. A colourless gas was evolved and after reaction was over, the solution was colourless.
(a) Name the powdered metal added to sodium hydroxide solution.
(b) Name the gas evolved.
(c) Name the salt present in the colorless solution.

Solution 10

Question 11

Name:
(a) A metallic hydroxide soluble in excess of NH₄OH
(a) A metallic oxide soluble in excess of caustic soda solution.
(b) A strong alkali
(c) A weak alkali.
(d) Two coloured ions
(e) Two bases which are not alkalis but dissolve in strong alkalis.
(f) A coloured metallic oxide which dissolves in alkalis to yield colourless solutions.

Solution 11

Chapter 4 - Analytical Chemistry Exercise 86

Question 1

What happens when ammonia solution is added
(a) Dropwise and then
(b) In excess to the following solutions:
(i) CuSO₄
(ii) ZnSO₄
(iii) FeCl₃
(c) Write balanced reactions.

Solution 1

Question 2

Name the chloride of a metal which is soluble in excess of ammonium hydroxide.

Solution 2

The chloride of a metal which is soluble in excess of ammonium hydroxide is zinc chloride i.e. ZnCl₂.

Question 3

On adding dilute ammonia solution to a colourless solution of a salt, a white gelatinous precipitate appears. This precipitate however dissolves on addition of excess of ammonia solution. Identify (Choose from Na, l, Zn, Pb, Fe)
(a) Which metal salt solution was used?
(b) What is the formula of white gelatinous precipitate obtained?

Solution 3

Question 4

Name
(a) A yellow monoxide that dissolves in hot and concentrated caustic alkali.
(b) A white, insoluble oxide that dissolves when fused with caustic soda or potash.
(c) A compound containing zinc in the anion.

Solution 4

(a) PbO
(b) Al₂O₃
(c) Na₂ZnO₂

Question 5

Fill in the blanks:
(a) Salts of ______ [normal / transition] elements are generally coloured. From the ions K¹⁺, Cr³⁺, Fe²⁺, Ca²⁺,  the ions generally coloured are ______.
(b) The hydroxide which is soluble in excess of NaOH is ______ [Zn(OH)₂ / Fe(OH)₃ / Fe(OH)₂].
(c) The salt which will not react with NH₄OH solution ______[ZnCl₂, CuCl₂ / NH₄Cl/ FeCl₂]
(d) The substance/s which react with hot conc. NaOH solution and undergoes a neutralization reaction ______ [Al₂O₃ / Al / Al(OH)₃]
(e) To distinguish soluble  salts of zinc and lead ______ [NaOH / NH₄OH]can be used.

Solution 5

(a) transition, Cr³⁺, Fe²⁺, MnO₄^4-.
(b) Zn(OH)₂
(c) NH₄Cl
(d) Al₂O₃, Al
(e) NH₄OH

Question 6

Choose the correct answer from the options given below :

(i) Color of ferrous ion is

(a) Blue

(b) Green

(c) Pink

(d) Light green

(ii) Which one is colourless anion?

 

(iii) Sodium zincate (Na₂ZnO₂) is

(a) Pale blue ppt

(b) Reddish brown ppt

(c) Colourless

(d) Dirty green ppt

(iv) Metal + alkali → salt + _________

(a) N₂

(b) H₂

(c) H₂O

(d) OH

(v) Which salt solution is soluble in excess of NH₄OH

(a) Iron (II) salts

(b) Iron (III) salts

(c) Lead salts

(d) Copper (II) salts

Solution 6

(i) Green

(ii)  

(iii) Colourless

(iv) H₂

(v) Copper(II) salts

Chapter 4 - Analytical Chemistry Exercise 87

Question 1

You are given a mixture of precipitated copper hydroxide and zinc hydroxide. Name a solvent which will dissolve:
(a) Only copper hydroxide
(b) Only zinc hydroxide
(c) Both copper hydroxide and zinc hydroxide

Solution 1

(a) Addition of KCN
(b) Addition of excess of NaOH.
(c) Addition of excess of NH₄OH.

Question 2

Using sodium hydroxide solution, how will you distinguish:
(a) Zinc nitrate solution from calcium nitrate solution
(b) Iron (II) chloride from iron (III) chloride
(c) Lead hydroxide from magnesium hydroxide.

Solution 2

Question 3

(a) Sodium hydroxide solution is added to solution A. A white precipitate is formed which is soluble in excess sodium hydroxide. Name the metal ion present in A.
(b) When ammonium hydroxide is added to solution B, a pale blue precipitate is formed. This pale blue precipitate dissolves in excess ammonium hydroxide to give an inky blue solution. Name the cation present in solution B. What is the probable colour of solution B?

Solution 3

(a) The metal ion present in solution A is Pb²⁺.
(b) The cation present in solution B is Cu²⁺. The probable colour of solution B is blue.

Question 4

What do you see when sodium hydroxide solution is added to zinc sulphate solution, till it is in excess?

Solution 4

Question 5

You are given three white powders-calcium carbonate, lead carbonate and zinc carbonate. Describe the tests you would carry out in solution, to identify the metal ion in each of the above compounds. Indicate clearly how you would prepare the solutions for the tests.

Solution 5

The solutions for the tests will be prepared by dissolving the given powders separately in water.
(i) Solution of Calcium carbonate:
Calcium carbonate is CaCO₃ and contains Ca²⁺ ions. Sodium hydroxide solution NaOH can be used to identify Ca²⁺ since its addition to calcium carbonate solution will give white precipitates of Ca(OH)₂ which are sparingly soluble in excess of NaOH.
(ii) Solution of Lead carbonate:
Lead carbonate is PbCO₃ and contains Pb²⁺ ions. Ammonium hydroxide solution NH₄OH can be used to identify Pb²⁺ since its addition to lead carbonate solution will give white precipitates of Pb(OH)₂ which are insoluble in excess of NH₄OH.
(iii) Solution of Zinc carbonate:
Zinc carbonate is ZnCO₃ and contains Zn²⁺ ions. Sodium hydroxide solution NaOH can be used to identify Zn²⁺ since its addition to zinc carbonate solution will give white gelatinous precipitates of Zn(OH)₂ which are soluble in excess of NaOH.

Question 6

Write equation for the reaction that will take place when copper sulphate solution is added to sodium hydroxide solution.

Solution 6

Question 7

Three test tubes contain calcium nitrate solution, zinc nitrate solution and lead nitrate solution. Each solution is divided into two portions (i) and (ii). Describe the effect of
(i) Adding sodium hydroxide solution to each portion in turn till it is in excess.
(ii) Adding ammonium hydroxide to each portion in turn till it is in excess.

Solution 7

Question 8

(a) Sodium hydroxide solution can be used to distinguish between i. iron (II) sulphate solution and (ii) iron (III) sulphate solution; because these solutions give different coloured precipitates with sodium hydroxide solution. Give the colour of the precipitate formed with each of the solution.
(b) What will you observe when barium chloride solution is added to iron(II) sulphate solution.
(c) How will the action of dilute hydrochloric acid on sodium carbonate and sodium sulphite enables you to distinguish between these two compounds?

Solution 8

Chapter 4 - Analytical Chemistry Exercise 88

Question 1

Describe in each case, one chemical test that would enable you to distinguish between the following pairs of chemicals. Describe what happens with each chemical or state 'no visible reaction'.
(i) Sodium chloride solution and sodium nitrate solution.
(ii) Sodium sulphate solution and sodium chloride solution.
(iii) Calcium nitrate solution and zinc nitrate solution.

Solution 1

Question 2

Write balanced equations for the following reactions:
(i) Iron(II) chloride solution with sodium hydroxide solution.
(ii) Chlorine and cold dilute sodium hydroxide solution.
(iii) Zinc and sodium hydroxide solution
(iv) Sulphur dioxide and sodium hydroxide solution
(Give the equation for the formation of the normal salt)

Solution 2

Question 3

State what do you observe when:
(i) Neutral litmus solution is added to alkaline solution
(ii) Ammonium hydroxide is added to iron (III) sulphate solution.
(iii) Lead nitrate and sodium chloride are mixed.
(iv) Ethane is bubbled through a solution of bromine in tetrachloromethane (carbon tetra chloride).
(v) Sulphur burns.

Solution 3

Question 4

Solution 4

Question 5

Write the observations, and balanced equations for the following reactions:
(i) Sodium hydroxide is added dropwise to a solution of zinc sulphate, till it is in excess.
(ii) Ammonium hydroxide is added first in a small quantity, and then in excess, to a solution of copper sulphate.
(iii) Excess of ammonium hydroxide is added to a substance, obtained by adding hydrochloric acid to silver nitrate solution.
(iv) Moist starch iodide paper is placed at the mouth of a test tube containing chlorine gas.
(v) A paper dipped in potassium permanganate solution is placed at the mouth of a test tube, containing sulphur dioxide gas.

Solution 5

Chapter 4 - Analytical Chemistry Exercise 89

Question 1

Solution 1

Question 2

The questions (i) to (v) refer to the following salt solutions listed A to F:
A. Copper nitrate
B. Iron (II) sulphate
C. Iron (III) chloride
D. Lead nitrate
E. Magnesium sulphate
F. Zinc chloride
(i) Which two solutions will give a white precipitate when treated with dilute hydrochloric acid followed by barium chloride solution/
(ii) Which two solutions will give a white precipitate when treated with dilute nitric acid followed by silver nitrate solution?
(iii) Which solution will give a white precipitate when either dilute hydrochloric acid or dilute sulphuric acid is added to it?
(iv) Which solution becomes a deep/inky blue colour when excess of ammonium hydroxide is added to it?
(v) Which solution gives a white precipitate with excess ammonium hydroxide?

Solution 2

(i) B and E (Iron (II) sulphate and Magnesium sulphate)
(ii) C and F (Iron (III) chloride and Zinc chloride)
(iii) D (Lead nitrate)
(iv) A (Copper nitrate)
(v) F (Zinc chloride)

Question 3

Solution 3

Chapter 4 - Analytical Chemistry Exercise 90

Question 1

Choose the correct answer:
The metal oxide which can react with acid as well as alkali is:
(a) Silver oxide.
(b) Copper (II) oxide.
(c) Aluminium oxide
(d) Calcium oxide

Solution 1

C ( Aluminium oxide)

Question 2

Identify the substances P, Q and R in each case based on the information given below:
(i) The deliquescent salt P, turns yellow on dissolving in water, and gives a reddish brown precipitate with sodium hydroxide solution.
(ii) The white crystalline solid Q is soluble in water. It liberates a pungent smelling gas when heated with sodium hydroxide solution.
(iii) The pale green solid R turns reddish brown on heating. Its aqueous solution gives a white precipitate with barium chloride solution. The precipitate is insoluble in mineral acids.

Solution 2

(i) P is Ferric chloride
(ii) Q is an ammonium salt
(iii) R is ferrous sulphate

Question 3

Give one chemical test to distinguish between the following pairs of compounds:
(i) Zinc sulphate solution and Zinc chloride solution.
(ii) Iron (II) chloride solution and iron (III) chloride solution.

Solution 3

(i) When BaCl₂ solution is added to the given solution ZnSO4 gives a white precipitate while no precipitate is obtained with ZnCl₂ solution.
(ii) When NaOH solution is added to the given solution, iron (II) chloride gives dirty green precipitate while reddish brown precipitate is obtained with iron(III) chloride.

Question 4

From the list given below, select the word (s) required complete the blanks (i) to (v) in the following passage :

Note : words chosen from the list are to be used only once. Write only the answers. Do not copy the passage, [ reddish brown, ammonium, nitrogen dioxide, hydroxyl, dirty green, ammonia, acidic, alkaline]

Nitrogen and hydrogen combine in the presence of a catalyst to give (i) ________ gas. When the above mentioned gas is passed through water it forms a solution which will be (ii) ______ in nature and the solution contains (iii) ______ ions and (iv) _______ions. The above solution when added to iron (II) sulphate solution gives a (v) _________coloured precipitate of iron (II) hydroxide

Solution 4

(i) Ammonia

(ii) Alkaline

(iii) Ammonium

(iv) Hydroxyl

(v) Dirty green

Question 5

Write the equation for the following reaction :

Zinc oxide is treated with sodium hydroxide solution.

Solution 5

Question 6

Choose the correct answer from the options given below :

(i) Hydroxide of this metal is soluble is sodium hydroxide solution

(a) Magnesium

(b) Lead

(c) Silver

(d) Copper

(ii) When dilute sulphuric acid reacts with iron sulphide, the gas evolved is _______

(a) Hydrogen sulphide

(b) Sulphur dioxide

(c) Sulphur trioxide

(d) Vapour of sulphuric acid

Solution 6

(i) Lead

(ii) Hydrogen sulphide

Chapter 4 - Analytical Chemistry Exercise 91

Question 1

State two relevant observations for each of the following:

(i) Ammonium hydroxide solution is added to copper (II) nitrate solution in small quantities and then in excess

(ii) Ammonium hydroxide solution is added to zinc nitrate solution in minimum quantities and then in excess

Solution 1

(i) (a) When NH₄OH is added to copper (II) nitrate solution in small quantities, a pale blue precipitate is observed.

 (b) When added in excess, NH₄OH dissolves to give an inky blue solution forming a complex salt.

(ii) (a) When NH₄OH is added to zinc nitrate solution in minimum quantity, it forms a gelatinous white precipitate.

 (b) When added in excess, it dissolves to form a complex salt.

Question 2

Distinguish between the following pairs of compound using the test given within brackets.

(i) Iron (II) Sulpate an and iron(III) using ammonium hydroxide)

(ii) A lead salt and a zinc salt (using excess ammonium hydroxide

Solution 2

(i) Iron (II):

 

Iron (III):

 

(ii) Pb(NO₃)₂+2 NH₄OH → Pb(OH)₂+2NH₄NO₃

On adding excess of NH₄OH, chalky white ppt. of

insoluble Pb(OH)₂ is formed.

ZnSO₄ + 2NH₄OH → Zn(OH)₂ + (NH₄)₂SO₄

With excess of NH₄OH, white gelatinous ppt. of soluble Zn(OH)₂ is formed.

Question 3

State your observations when ammonium hydroxide solution is added drop by drop and then in excess to each of the following solutions :

(i) Copper sulphate solution

(ii) Zinc sulphate solution

Solution 3

i) When NH₄OH is added to copper sulphate solution drop-wise, a pale blue ppt. is obtained.

 CuSO₄ + 2NH₄OH → Cu(OH)₂ + (NH₄)₂SO₄ + 4H₂O

  With excess of NH₄OH, the ppt. dissolves to give a deep blue solution of tetra amine copper (II) sulphate.

 Cu(OH)₂ + (NH₄)₂SO₄ + NH₄OH →  [Cu(NH₃)₄]SO₄ + H₂O

ii) When NH₄OH is added to zinc sulphate solution drop-wise, a white, gelatinous ppt. is obtained.

 ZnSO₄ + 2NH₄OH →  Zn(OH)₂ + (NH₄)₂SO₄

 With an excess of NH₄OH, the ppt. dissolves to give a colourless solution of tetra amine zinc (II) sulphate.

 Zn(OH)₂ + (NH₄)₂SO₄ + 2NH₄OH → [Zn(NH₃)₄]SO₄ + 4H₂O

Question 4

Fill in the blank from the choices given in bracket.

Potassium sulphite on reacting with hydrochloric acid releases ________

Solution 4

Potassium sulphite on reacting with hydrochloric acid releases sulphur dioxide.

Question 5

Choose the correct answer from the options given below :

A chloride which forms a precipitate that is soluble in excess of ammonium hydroxide is :

(a) Calcium chloride

(b) Ferrous chloride

(c) Ferric chloride

(d) Copper chloride

Solution 5

Copper chloride