KVPY Solution 20-10-10

KVPY QUESTION WITHANSWER(20-10-10)

1.

Sol.

The number of intege integers rs n for which the value of

(A) p-hydroxybenzoic acid.

(A*) 2 (C) 1

(C) Benzoic acid.

(B*) o-nitrobenzoic acid.

(B) 4 (D) 5

 n(10  n)   <0 log10    16  

        

n(10  n) 0< <1 16 0 < n (10  – n) < 16 n (10  – n) > 0 n (n  – 10) < 0 n  (0, 10)...(i) n(10  – n)  – 16 < 0 10n  – n2  – 16 < 0 n2  – 10n + 16 > 0 n2  – 8n  – 2n + 16 > 0 (n  – 8)  – 2 (n  – 8) > 0 (n  – 2) (n  – 8) > 0 n  ( – , 2)  (8, ) ....(ii) Using (i) & (ii)

0 1 2

8 9 10

 Possible value which are integers are 1 and 9  2 values are possible.

Sol.

The strongest acid amongst the following is

 n(10  n)   become negative is : log10    16  



2.

3.

An electrical healting coil was placed in a calorimeter containing 360 gm of water at 10ºC .The coil consumes energy at the rate of 90 watt. The water equivalent of the calorimeter and the coil is 40 gm. Calculate what will be the temperature of water after 10 minutes. (J = 4.2 Joules / cal.) (A*) 42.14 ºC (B) 40.14 ºC (C) 44.14 ºC (D) 14.42 ºC Energy supplied by coil = heat gain by water and calorimetry  Pt = (m 1 + w) × S  90 × (10 × 60) = (360 + 40) × 4.2 × (   – 10)  = 42.14ºC

(D) Cyclohexanecarboxylic acid. Sol.

In benzoic acid, the carbon atoms, which are present in the ring, are sp2 hybridised. As a result, benzoic acid is a stronger acid than cyclohexane carboxylic acid. Also, electron-withdrawing groups substituted at the ortho and para positions, enhance the acidic strength.

4.

Miller synthesized synthesized simple amino acids from (A*) H2, NH NH3, CH CH4 and water vapours (B) NH3, CH4, CN and O2 (C) CH4, CN, H2 and O2 (D) H2, O2, N2 and H2O