CHEMISTRY (FULL TEST- II)

 

CHEMISTRY (FULL TEST- II)

 

Time : Two Hours                                                                          Maximum Marks : 100

 

 

NOTE :

 

(i)         Attempt all questions.

(ii)        Start each question on a fresh page.

(iii)       Answers of all parts of a question should be given at one place.

(iv)       Each question carries TEN Marks.

(v)        Use of calculator is NOT PERMITTED.

(vi)       Use of logarithmic table is PERMITTED.

 

 

 

 

 

 

 

 

           

 

 

 

 

 

 

 

 

 

 

Name of the candidate                     :           ………………………………………..

Enrollment Number                          :           ………………………………………..

 

 

 

1. The conversion of trypsinogen (A) into trypsin (B) in an autocatalytic reaction A ® B, where B catalyzes the reaction. The rate equation is = kxy, where x and y are concentrations of trypsinogen and tripsin at time t. Integrate this equation for initial conc. = X₀ and Y₀ for A and B and show that kt = .
2. The molar volume of helium at 10.1325 MPa and at 273 K is 0.011705 of its molar volume at 101.325 K Pa at 273 K. Calculate the radius of helium atom.

 

3. A 1.0 ´ 10^–3 M solution of AgNO₃ is made 0.20 M in NH₃. What are the concentrations of Ag⁺, Ag (NH₃)⁺, Ag(NH₃)₂⁺, in the resulting solution.

Given Ag(NH₃)₂⁺  Ag(NH₃)⁺ + NH₃, k₁ = 1.4 ´ 10^–4 M

Ag(NH₃)⁺  Ag⁺ + NH₃, k₂ = 4.3 ´ 10^–4 M

4. The temperature of air decreases linearly with altitude in accordance with the equation T = T₀ – ah, where a = constant, h = altitude, T₀ = temperature at the ground level, T is the temperature at the altitude. Then prove that the barometric relation

ln ln T₀ = ln (T₀ – ah).

5. H₂S is bubbled into a 0.2 M NaCN solution which is 0.02 M in each and . Determine which sulphide precipitate first

Given K_sp (Ag₂S) = 1 × 10^-50 M³

K_sp (CdS) = 7.1 × 10^-28 M²

K inst  = 1.0 × 10^-20+ M²

K inst (CdI₄]^-2 = 7.8 × 10^-18 M⁴

 

 

6. Identify A to E in the following

(a)		(b)
(c)		(d)
(e)

7. Compound (A), M.F C₆H₁₂O₂ reduces ammonical silver nitrate to metallic silver and looses its optical activity on strong heating yielding (B), C₆H₁₀O which readily reacts with dilute KMnO₄. (A) on oxidation with alkaline KMnO₄ gives (C) having M.F C₆H₁₀O₃ which decarboxylates readily on heating to 3-pentanone. The compound (A) can be synthesized from a carbonyl compound having M.F. C₃H₆O on treatment with dilute NaOH. Oxidation of (B) with ammonical silver nitrate followed by acidification gives (D). (D) forms a derivative (E) with SOCl₂ which on reaction with H₃CNHCH₂CH₃ yields (F). Identify (A) to (F) giving proper reaction sequences. What is the name reaction involved in the conversion of C₃H₆O to (A)?
8. A compound ‘A’ C₁₃H₁₀BrNO, which is sparingly soluble in cold water, dissolved on boiling with conc. HCl. When cooled the resulting solution deposited a solid B, C₇H₆O₂, which displaced CO₂ from Na₂CO₃ solution. Basification of the solution which remained yielded a solid C, which contained C = 41.9%, H = 3.5%, Br = 46.5% and N = 8.1%.

Treatment of ice cold solution of C in HCl with NaNO₂ followed by Copper (I) bromide gives compound D. The reaction of D with fuming HNO₃ and conc. H₂SO₄ gives only one compound E. Identify A to E with proper reasoning.

9. i) A black coloured compound (B) is formed on passing H₂S through the solution of a compound (A) in NH­₄OH.
10. ii) (B) on treatment with HCl and KClO₃ gives (A)

iii)   (A) on treatment with KCN gives a buff coloured ppt. which dissolves in excess of this reagent forming a compound (C).

1. iv) The compound (C) is changed into a compound (D) when its aqueous solution is boiled.
2. v) The solution of (A) was treated with excess of NaHCO₃ and then with Br₂ On cooling and shaking for some time, a green colour of compound (E) is formed. No change is observed on heating.

Identify (A) to (E) and give chemical equations for the reaction at steps (i) to (v)

10. A white powder (A) on heating gives a colourless gas (B) and a solid (C). The compound (C) assume a yellow colour on heating and changes to white on cooling. If  dissolves in dilute acids and the resulting solution gives a white precipitate with K₄Fe(CN)₆. Further (A) dissolves in dil HCl with the evolution of a gas, which is the same as B, which turns lime water milky. The solution so obtained gives a white precipitate  (D) with H₂S in the presence of NH₄OH. Another portion of the solution gives initially a precipitate (E) with NaOH solution, which dissolves in excess of the base. Identify the compounds (A) to (E)