Advertisements
Advertisements
Which of the following are example of synthetic rubber?
(i) Polychloroprene
(ii) Polyacrylonitrile
(iii) Buna-N
(iv) cis-polyisoprene
Concept: undefined >> undefined
Vulcanisation makes rubber:
(i) more elastic
(ii) soluble in inorganic solvent
(iii) crystalline
(iv) more stiff
Concept: undefined >> undefined
Advertisements
Identify the polymer given below:
Concept: undefined >> undefined
Match materials given in Column I with the polymers given in Column II.
| Column I | Column II |
| (i) Natural rubber latex | (a) Nylon |
| (ii) Wood laminates | (b) Neoprene |
| (iii) Ropes and fibres | (c) Dacron |
| (iv) Polyester fabric | (d) Melamine formaldehyde resins |
| (v) Synthetic rubber | (e) Urea-formaldehyde resins |
| (vi) Unbreakable crockery | (f) cis-polyisoprene |
Concept: undefined >> undefined
Solutions of two electrolytes ‘A’ and ‘B’ are diluted. The Λm of ‘B’ increases 1.5 times while that of A increases 25 times. Which of the two is a strong electrolyte? Justify your answer. Graphically show the behavior of ‘A’ and ‘B’.
Concept: undefined >> undefined
The molar conductivity of CH3COOH at infinite dilution is 390 Scm2/mol. Using the graph and given information, the molar conductivity of CH3COOK will be:
Concept: undefined >> undefined
Which of the following statements is not correct for amines?
Concept: undefined >> undefined
Molar conductivity of substance “A” is 5.9 × 103 S/m and “B” is 1 × 10–16 S/m. Which of the two is most likely to be copper metal and why?
Concept: undefined >> undefined
Explain the following reaction:
Cannizzaro reaction
Concept: undefined >> undefined
Give reasons for the following statement:
Copper does not displace hydrogen from acids.
Concept: undefined >> undefined
What happens when methanal undergoes cannizzaro reaction?
Concept: undefined >> undefined
Which of the following solutions of KCl will have the highest value of molar conductivity?
Concept: undefined >> undefined
Assertion (A) : Conductivity decreases with decrease in concentration of electrolyte.
Reason (R) : Number of ions per unit volume that carry the current in a solution decreases on dilution.
Concept: undefined >> undefined
What happens when (CH3)3 C – OH is heated with Cu/573 K?
Write the chemical equation in support of your answer.
Concept: undefined >> undefined
Write the structures of A, B and C in the following reaction:
Concept: undefined >> undefined
Conductivity of 2 × 10−3 M methanoic acid is 8 × 10−5 S cm−1. Calculate its molar conductivity and degree of dissociation if `∧_"m"^0` for methanoic acid, is 404 S cm2 mol−3.
Concept: undefined >> undefined
Which of the following does not give Cannizzaro reaction?
Concept: undefined >> undefined
Assertion (A): Molar conductivity decreases with increase in concentration.
Reason (R): When concentration approaches zero, the molar conductivity is known as limiting molar conductivity.
Concept: undefined >> undefined
Which of the following alcohols will not undergo oxidation?
Concept: undefined >> undefined
The following questions are case-based questions. Read the passage carefully and answer the questions that follow:
| Rahul set up an experiment to find the resistance of aqueous KCl solution for different concentrations at 298 K using a conductivity cell connected to a Wheatstone bridge. He fed the Wheatstone bridge with a.c. power in the audio frequency range 550 to 5000 cycles per second. Once the resistance was calculated from the null point, he also calculated the conductivity K and molar conductivity ∧m and recorded his readings in tabular form. |
| S. No. | Conc. (M) |
k S cm−1 | ∧m S cm2 mol−1 |
| 1. | 1.00 | 111.3 × 10−3 | 111.3 |
| 2. | 0.10 | 12.9 × 10−3 | 129.0 |
| 3. | 0.01 | 1.41 × 10−3 | 141.0 |
Answer the following questions:
(a) Why does conductivity decrease with dilution? (1)
(b) If `∧_"m"^0` of KCl is 150.0 S cm2 mol−1, calculate the degree of dissociation of 0.01 M KCI. (1)
(c) If Rahul had used HCl instead of KCl then would you expect the ∧m values to be more or less than those per KCl for a given concentration? Justify. (2)
OR
(c) Amit a classmate of Rahul repeated the same experiment with CH3COOH solution instead of KCl solution. Give one point that would be similar and one that would be different in his observations as compared to Rahul. (2)
Concept: undefined >> undefined
