Page 36 - Chemistry - XI

Q4. Why boiling tubes of same size are used in experiment?
Ans. It is because, the accurate comparison can be done.
Q5. When HCl is added to cobalt chloride solution, what type of compound is formed?
Ans. A complex compound [CoCl ] is formed.
2–
4
Q6. Why is it suggested to use test tubes of the same diameter and thickness for the comparison of
colour of the solution?
Ans. It is done so as to make the comparison easier.

Q7. Is the formation of complex an exothermic process or an endothermic process?
Ans. It is an exothermic process.

COMPETENCY BASED QUESTIONS

Multiple Choice Questions

Q1. What is the colour of [Co(H O) ] ?
2+
2 6
(a) Pink (b) Blue (c) Red (d) Green
Q2. What is coordination number of Cobalt in [CoCl ] ?
2–
4
(a) 2 (b) 4 (c) 6 (d) 8
Q3. The colour of [Fe(SCN)] complex is
2+
(a) green (b) blue (c) blood red (d) colourless

Q4. Value of ‘K’ changes with change in
(a) catalyst (b) concentration (c) temperature (d) All of these

Q5. Which of the following is the correct formula of Ammonium thiocyanate?
(a) NH CN (b) NH CNO (c) NH SCN (d) NH NCS
4 4 4 4
Q6. The colour of [CoCl ] is
2–
4
(a) green (b) blue (c) pink (d) colourless
Q7. What is coordination number of Fe in [Fe(H O) (SCN)] ?
2+
2 5
(a) 4 (b) 5 (c) 6 (d) 8
Q8. What will happen to colour intensity on dilution?

(a) Increases (b) Decreases
(c) Remains same (d) Will increase appreciably

Q9. How do you know when equilibrium is reached?
(a) Intense red colour (b) Light red colour
(c) Constant intensity of red colour (d) None of these

Answer key
Answer
Answer key key
1. (a), 2. (b), 3. (c), 4. (c), 5. (d), 6. (b), 7. (c), 8. (c), 9. (c)
1. (a), 2. (b), 3. (c), 4. (c), 5. (d), 6. (b), 7. (c), 8. (c), 9. (c)
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