NEET TEST SERIES 158 CHEMISTRY

3. When one mole of an ideal gas is compressed to half its initial volume and simultaneously heated to twice in initial temperature, the change in entropy (ΔS ) is

a) C_V In2

b) C_P In2

c) R In 2

d) (C_V -R) In 2

4. The geometry of and are Ni(CO)₄ and  [Ni(PPh₃)₂ Cl₂] are

(a) both square planar     
(b) tetrahedral and square planar
(c) both tetrahedral   
(d) None of these  

5. For the reaction of one mole of zinc dust with one mole of sulphuric acid in a bomb calorimeter, and w corresponds to

(a) ΔU < 0, w = 0
(b) ΔU < 0, w < 0
(c) ΔU > 0, w = 0
(d) ΔU >0, w > 0

6. Reactivity of hydrogen atoms attached to different carbon atoms in alkanes has the order

(a) Tertiary> Primary > Secondary
(b) Primary > Secondary > Tertiary
(c) Both (a) and (b)
(d) Tertiary > Secondary > Primary

7. In most cases, for a rise of 10 K temperature the rate constant is doubled to tripled. This is due to the reason that

(a) collision frequency increases by a factor of 2 to 3.
(b) fraction of molecules possessing threshold energy increases by a factor of 2 to 3.
(c) Activation energy is lowered by a factor of 2 to 3.
(d) none of these

8. Which of the following colligative property can provide molar mass of proteins (or polymers or colloids) with greatest precision?

(a) Osmotic pressure           
(b) Elevation of boiling point
(c) Depression of freezing point
(d) Relative lowering of vapour pressure

9. Which one of the following reactions will not form acetaldehyde?

10. The reason for double helical structure of DNA is the operation of:

(a) Electrostatic attractions
(b) van der Waals forces
(c) Dipole – Dipole interactions
(d) Hydrogen bonding

11. Assertion : Threshold frequency is the maximum frequency required for the ejection of electron from the metal surface.
      Reason : Threshold frequency is characteristic of a metal.

a) If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.
b) If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.
c) If the Assertion is correct but Reason is incorrect
d) If the Assertion is incorrect but Reason is correct.

15. An open beaker of water in equilibrium with water vapour is in a sealed container. When a few grams of glucose are added to the beaker of water, the rate at which water molecules:

(a) leaves the vapour increases
(b) leaves the solution increases
(c) leaves the solution decreases
(d) leaves the vapour decreases

20. Statement I: In secondary structure of DNA adenine forms hydrogen bonds with guanine whereas cytosine forms hydrogen bonds with thymine.

     Statement II: RNA molecules are of three types m-RNA, r-RNA and t-RNA and they all perform different functions.

(a) Both statement I and II are correct.
(b) Both statement 1 and II are incorrect.
(c) Statement I is correct but statement II is incorrect.
(d) Statement II is correct but statement I is incorrect.