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Basic Chemistry Past Papers

Paper# 1

[OBJECTIVE]

Subject: Fundamentals of Chemistry (Basic Chemistry)

Time Allowed: 15 Min

Maximum Marks: 10

NOTE: Attempt this Paper on this Question Sheet only. Please encircle the correct option. Division of marks is given in front of each question. This Paper will be collected back after expiry of time limit mentioned above.

 

Part-I Encircle the right answer, cutting and overwriting is not allowed. (1×10=10)

1. Which type of radioactive decay results in an increase in atomic number?

(a) α emission                                   (b) β emission

(c) Positron emission                      (d) µ emission

2. Which of following is an a particles _______

(a) 2He4                                                                 (b) 2He5

(c) 2He3                                                                 (d) 2He6

3. Nuclear reaction proceeds with change in composition of

(a) Electrons                                       (b) Nucleus

(c) Electronic configuration          (d) Ail of above

4. Which is a strong base?

(a) Phenol                                           (b) Ammonia

(c) Nitrobenzene                             (d) Pyridine

5. Neutron was discovered by

{a) Heisenberg                                  (b) Chadwick

(c) Rydberg                                         (d) Plank

6. Which of the following is P-block element.

(a) Cr                                                     (b) S

(c) Zn                                                     (d) Ca

7. 2S02+ O2 ⇌ 2S03 In this reaction, the increase In pressure will shift the reaction

{a} Formation of SO3                       (b) Decomposition of SO3

(c) Reaction remains equilibrium (d) Reaction will not be affected by pressure

In periodic table, atomic size of elements increases going from

(a) Left to right in a period           (b) Bottom to Top in a group

(c) Top to bottom in a group       (d) All of the above

9. 3H2+N2 ⇌ 2NH3 In this reaction, the increase in hydrogen concentration will shift the reaction

(a} Formation of NH3                      (b) Decomposition of NH3

(c) Formation of N2                         (c) Reaction will not be affected by pressure

10. Reaction rates can change with

(a) Temperature                              (b) Catalyst

(c} Reactant concentrations        (d) Ail of above

 

 

 

[SUBJECTIVE]

Subject: Fundamentals of Chemistry (Basic Chemistry)

Time Allowed: 2 Hrs. 45 Min

Maximum Marks: 50

NOTE: ATTEMPT THIS (SUBJECTIVE) ON THE SEPARATE ANSWER SHEET PROVIDED

 

Part-II Give short answers! (20)

Q#1. Draw the resonance structures of aniline. (2)

Q#2. Why Cl-CH2COOH is more acidic as compare CH3COOH? (2)

Q#3. Define half-life period of a chemical reaction, give one example of its measurement. (2)

Q#4. Why gases behave non-ideal at low temperature and high pressure? (2)

Q#5. Differentiate between nuclear and chemical reactions. (2)

Q#6. Describe main difference between atomic emission and atomic absorption spectra. (2)

Q#7. Define order of a reaction, how it can be measured? (2)

Q#8. What are buffers, briefly explain your answer with one example. (2)

Q#9. Why BF3 is considered as Lewis acid? (2)

Q#10. Briefly, explain why phenol is acidic in nature as compare to ethanol? (2)

 

Part-III Answer the following long questions. (30)

Q#1 (a) What is half-life of a radioactive element? Derive an expression for calculating half-life. (6)

(b) Explain the effect of pressure and temperature on Haber-Bosch process of NH3 synthesis. (4)

Q#2 (a) Calculate the radius of electron in hydrogen atom. (6)

(b) What are ortho/para and meta directing groups, explain your answer with examples. (4)

Q#3 (a) Discuss the variation of ionization energy within a group and in period. (4)

(b) With the help of molecular orbital theory explain why N2 is diamagnetic and O2 is paramagnetic in nature. (6)

 

 

 

Paper# 2

[OBJECTIVE]

Subject: Fundamentals of Chemistry (Basic Chemistry)

Time Allowed: 15 Min

Maximum Marks: 10

NOTE: Attempt this Paper on this Question Sheet only. Please encircle the correct option. Division of marks is given in front of each question. This Paper will be collected back after expiry of time limit mentioned above.

 

Part-I Encircle the right answer, cutting and overwriting is not allowed. (1×10=10)

1. In Hydrogen spectra, which series is in visible region?

(a) Pfund                                             (b) Paschen

(c) Lyman                                            (d) Balmer

2. What is the product of this reaction 2He4 + 4Be9

(a) 6C12+ 0n1                                        (b) 6C130n0

(c} 6C12+ 2n1                                        (d) 6C12 + 1n1

3. Phenol is

(a) Acidic                                              (b) Basic

(c) Neutral                                          (d) Amphoteric

4. Davison and Germer experimentally shows that

(a) Mass of electron                       (b) Radioactivity

(c) Charge of electron                    (d) Wave nature of electron

5. The explanation of photoelectric effect is given by

(a) Heisenberg                                  (b) Einstein

(c) Rydberg                                         (d) Plank

6. A dynamic equilibrium

(a) Is a form of static equilibrium (b) never exist

(c) Involves radioactivity               (d) is when forward and backward reaction rate are equal

7. A reaction in which all reactants are in same phase is called

{a) Heterogeneous                         (b) Simple

(c) Homogenous                              (d) Complex

8. PCl5 ⇌ PCl3 + Cl2 In this reaction, the increase in pressure will shift the reaction

{a) Formation of PCl5                      (b) Decomposition of PCl5

(c) Reaction remains equilibrium               (d) Reaction will not be affected by pressure

9. H2+l2 ⇌ 2HI in this reaction, the increase in pressure will shift the reaction

(a) Formation of HI                          (b) Decomposition of Hi

(c) Formation of H2 and I⇌2         (d) Reaction will not be affected by pressure

10. What is the range of visible spectrum?

(a) 200-350 nm                                  (b) 400-750 nm

(c) 200-350 mm                                 (d) 400-750 mm

 

 

[SUBJECTIVE]

Subject: Fundamentals of Chemistry (Basic Chemistry)

Time Allowed: 2 Hrs. 45 Min

Maximum Marks: 50

NOTE: ATTEMPT THIS (SUBJECTIVE) ON THE SEPARATE ANSWER SHEET PROVIDED

 

Part-II Give short answers! (20)

Q#1. Iodo acetic acid is ten times less acidic than chloro acetic acid.

Q#2. What is 1st order reaction? Give units of 1st order rate constant.

Q#3. The C-Cl bond length is shorter in vinyl chloride than in CH3CH2Cl.

Q#4. Define the term refractive index and give its unit. .

Q#5. Write down Bragg’s equation and give the meaning of various parameters in it.

Q#6. Write down two causes for deviation of gases from ideal behavior.

Q#7. Name the factors that govern the ionization energy of an element.

Q#8. Predict the name of shapes or geometry of following molecules, using VESPER model.

(a) CCl4 (b) H2Se (c) AsF3 (d) AICI3

Q#9. Why do lighter elements generally undergo fusion while heavier elements show nuclear fission?

Q#10. How do you prove that half-life period of a first order reaction is independent of initial concentration of reactant?

Part-III Questions with brief answers

Q#1 (a) Define surface tension. Give its SI units. How it can be measured? (5)

(b) How ionization potential and electro negativity vary in the periodic table. (5)

Q#2 (a) What is order of reaction? Derive kinetic equation for 2nd order reaction when initially concentration of both reactants is same. (5)

(b) Compare and contrast the Valence bond and Molecular orbital theories. (5)

Q#3 (a) what is radioactivity? Prove that for a radioactive element tin is 0.693/k where k is decay constant. (5)

(b) Discuss the diffraction of X-rays. (5)

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