Case study based questions -Solution (Chemistry)

1. Read the given passage and answer the questions that follow: 

    An ideal solution may be defined as the solution which obeys Rault’s law exactly over the entire range of concentration. The solutions for which vapour pressure is either higher or lower than that predicted by Rault’s law are called non-ideal solutions. Non-ideal solutions can show either positive or negative deviations from Rault’s law depending on whether the A-B interactions in solution are stronger or weaker than A-A or B-B interactions. The following questions are multiple choice questions. Choose the most appropriate answer:

i). Which of the following solutions is/are ideal solution(s)?

    (I) Bromoethane & Iodoethane  

    (II) Acetone & Chloroform 

    (III) Benzene & Acetone 

    (IV) n-heptane & n-hexane 

(a) Only I

(b) I and II

c) II and III

d) I and IV

Ans- d

ii). For which of the following solutions ∆Hmix and ∆Vmix is negative? 

(a) Acetone and Aniline

b) Ethyl alcohol and cyclohexane

c) Acetone and CS2

d) Benzene and toluene

(iv) Following figure show which type of deviation from Raoult's law. 

a. Positive deviation

b. Negative deviation

c. Positive and negative deviation

d. None of these

Ans-b

(V). Water-Ethanol mixture shows 

    I). Positive deviations 

    II). Forms minimum boiling azeotropes 

    III). Shows negative deviations 

    IV). Forms maximum boiling azeotropes.

(a) I and II

(b) II and III

(c) I and IV

(d) III and IV

Ans-a