When 2-bromo-2-methylbutane is treated with a base, a mixture of 2-methyl-2-butene and 2-methyl-1-butene is produced. When potassium hydroxide is the base, 2-methyl-1-butene accounts for 45% of the product mixture. However, when potassium tert-butoxide is the base, 2-methyl-1-butene accounts for 70% of the product mixture. What percent of 2-methyl-1-butene would be in the mixture if potassium propoxide were the base

The percentage mixture of 2-methyl-1-butene would be in between the 45% and 70%.

Explanation:

Potassium prop oxide is the intermediate base as compared to the potassium hydroxide which is less bulky strong base and potassium tert-butoxide which is bulky base. Bulky base can minimize the substitution reaction by causing hinders the approach of carbon attack and KOH is the strong base which less effective in minimizing the substitution reaction.