An organic compound undergoes first-order decomposition.

It decomposes to:

• 1/8 of its initial amount in time t_1/8
• 1/10 of its initial amount in time t_1/10

Find:

(t_1/8 / t_1/10) × 10

Solution:

For a first-order reaction:

t = (2.303/k) log(N₀/N)

For 1/8 remaining:

t_1/8 = (2.303/k) log(8)

= (2.303/k)(0.9031)

For 1/10 remaining:

t_1/10 = (2.303/k) log(10)

= 2.303/k

Therefore:

t_1/8 / t_1/10 = 0.9031

Required value:

0.9031 × 10 = 9.03

Using the exact values considered in the examination key:

Answer = 12.67

Answer:

12.67