Chemical Analysis Quiz | Chemistry Quiz
Analytical chemistry deals with qualitative and quantitative analysis of substances.
Qualitative analysis: A salt consists of two parts known as radicals. The positively charged part of a salt (cation) which has been derived from a base is termed as basic radical and the negatively charged part of salt (anion) which has been derived from acid is termed as acidic radical. In the qualitative inorganic analysis, the given compound is analyzed for the basic and acid radicals (i.e., the cations and the anions), that it contains.
Analysis of Inorganic Salts
It involves the following steps : (1) Preliminary tests (2) Wet tests for acid radicals and (3) Wet tests for basic radicals.
(1) Preliminary tests
(i) Physical examination: It involves the study of color, smell, density etc.
(ii) Dry heating: Substance is heated in a dry test tube.
(iii) Flame test
Characteristic flame colour : Certain metals and their salts impart specific colours to Bunsen burner flame.
(a) Pb imparts pale greenish colour to the flame.
(b) Cu and Cu salts impart blue or green colour to the flame.
(c) Borates also impart green colour to the flame.
(d) Ba and its salts impart apple green colour to the flame.
(e) Sr imparts crimson red colour to the flame.
(f) Ca imparts brick red colour to the flame.
(g) Na imparts yellow colour to the flame.
(h) K imparts pink-violet (Lilac) colour to the flame.
(iv) Borax bead test : The transparent glassy bead when heated with inorganic salt and the colour produced gives some idea of cation present in it.
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1. Sodium sulphite on heating with dilute HCl liberates a gas which
(a) Turns lead acetate paper black
(b) Turns acidified potassium dichromate paper green
(c) Burns with a blue flame
(d) Smells like vinegar
SOL:(b)
2. Starch-iodide paper is used for the test of
(a) Iodine
(b) Iodide ion
(c) Oxidising agent
(d) Reducing agent
SOL : (a) Starch Iodide paper is used for the test of Iodine, as
3. Which of the following is coloured compound?
(a) CuF2 (b) Cul
(c) NaCl (d) MgCl2
SOL : A
4. The alkaline earth metal that imparts apple green colour to the bunsen flame when introduced in it in the form of its chloride is
(a) Barium (b) Strontium
(c) Calcium (d) Magnesium
SOL : (a) Ba2+ imparts green colour to the flame.
5. Blue borax bead is obtained with
(a) Zn (b) Cobalt
(c) Chromium (d) Fe
SOL : (b)
6. In laboratory burners, we use
(a) Producer gas (b) Oil gas
(c) Gobar gas (d) Coal gas
SOL : A
7. Chromyl chloride vapours are dissolved in NaOH and acetic acid and lead acetate solution is added, then
(a) The solution will remain colourless
(b) The solution will become dark green
(c) A yellow solution will be obtained
(d) A yellow precipitate will be obtained
SOL : (d)
8. A brown ring appears in the test for
(a) Nitrate (b) Nitrite
(c) Bromide (d) Iron
SOL : (a) At the junction of salt solution and FeSO4 solution with conc. H2SO4 a brown ring is obtained
9. The gas which is absorbed by ferrous sulphate solution giving blackish brown colour is
(a) NO (b) CO
(c) N2 (d) NH2
SOL : (a)
10. A reagent that can distinguish between a chloride and a peroxide is
(a) Water (b) Dil. H2SO4
(c) KOH solution (d) NaCl
SOL : (b) Dil. H2SO4 doesn’t react with chloride but reacts with peroxide
11. Which reagent below would enable you to remove sulphate ions from a solution containing both sulphate and chloride ions
(a) Sodium hydroxide
(b) Barium hydroxide
(c) Barium sulphate
(d) Potassium hydroxide
SOL : (b) Ba(OH)2 is not highly basic and bond is not easily broken
12. The compound insoluble in acetic acid is
(a) Calcium oxide
(b) Calcium carbonate
(c) Calcium oxalate
(d) Calcium hydroxide
SOL : (c) Calcium oxalate will not dissolve in acetic acid (weak acid) but only in strong acid
Chemical Analysis Quiz | Chemistry Quiz
13. Which of the following radicals will not be precipitated by passing H2S in concentrated acid solution
(a) Copper (b) Antimony
(c) Arsenic (d) Cadmium
SOL : (d) As cadmium belongs to the IInd group and is precipitated as sulphide and not as chloride
14. In the analysis of basic radicals, the group reagent H2S gas is generally used in the groups
(a) I and II groups
(b) II and III groups
(c) III and V groups
(d) II and IV groups
SOL : D
15. Which of the following is not precipitated as sulphide by passing H2S in presence of conc. HCl
(a) Copper (b) Arsenic
(c) Cadmium (d) Lead
SOL : (c) Cd2+ is not precipitated by H2S in concentrated acid solution that is why the solution is diluted before passing H2S through it.
16. Mark the compound which turns black with
(a) Lead chloride
(b) Mercurous chloride
(c) Mercuric chloride
(d) Silver chloride
SOL : B
17. Colour of cobalt chloride solution is
(a) Pink (b) Black
(c) Colourless (d) Green
SOL : (a) Colour of anhydrous COCl2 is blue and when it comes in contact with moisture then it turns in pink.
18. In the titration of strong acid and weak base, the indicator used is
(a) Thymol blue
(b) Phenolphthalein
(c) Thymolphthalein
(d) Methyl orange
SOL : D
19. What will be the volume of a 12 M solution, if it is equivalent to 240 ml 18 M solution
(a) 6 litre (b) 600 litre
(c) 400 litre (d) 0.36 litre
SOL : (d)
20. If we use phenolphthalein as an indicator in a titration of Na2CO3 with HCl the usual result is
(a) No visible change will occur
(b) The indicator reacts with the acid
(c) The indicator reacts with the base
(d) Sodium chloride and carbonic acid will be formed
SOL : (a) The resulting solution is colourless.
21. Methyl orange gives red colour in
(a) Sodium carbonate solution
(b) Sodium chloride solution
(c) Hydrochloric acid solution
(d) Potassium hydroxide solution
SOL : (c) As it is a weak aromatic base so it gives colour in acidic medium.
22. Cosin used to detect end point of precipitation titration by adsorption is called
(a) Absorption indicator (b) Adsorption indicator
(c) Chemical indicator (d) Normal indicator
SOL : B
23. A chemistry student trying to detect the metallic ion in a salt, makes a paste on a clean platinum wire loop of the salt with concentrated HCl. When he takes a small amount of this paste and keeps it in a non-luminous Bunsen flame, the colour of the flame changes to grassy green. He should, therefore, conclude that the metal is
(a) Barium (b) Calcium
(c) Potassium (d) Strontium
SOL : (a) 'Ba' gives characteristic green flame in Bunsen burner.
24. Mixture is heated with dil. H2SO4 and the lead acetate paper turns black by the evolved gases. The mixture contains
(a) Sulphite
(b) Sulphide
(c) Sulphate
(d) Thiosulphate
SOL : (b)It must be sulphide as