Question

Finely divided catalyst has greater surface area and has greater catalytic activity than the compact solid. If a total surface area of 6291456 cm2 is required for adsorption in a catalysed gaseous reaction, then how many splits should be made to a cube of exactly 1 cm in length to achieve required surface area.

(Given : One split of a cube gives eight cubes of same size)

• A. (a) 60
• A. (b) 80
• A. (c) 20
• A. (d) 20

Answer 1

(c)

Sol. Total surface area of eight cubes $= 8 \times 6 \times \left( \frac { 1 } { 2 } \times \frac { 1 } { 2 } \right)$

Apply the formula

Surface area on n split of a cube $= 8 ^ { n } \times 6 \times \left( \frac { 1 } { 2 } \right) ^ { 2 n }$

6291456