Which of the two reactions proceed faster ?

Which of the following reactions proceed at low pressure?

Which of the following reactions proceed at low pressure?

Which of the following reactions proceeds through an alkylsodium intermediate ?

Which of the folowing reaction proceeds via formation of carbacation ?

Zinc piece and zinc powder are taken in two test tubes and equal amount of dil. HCl is added. In which test tube does the reaction proceed faster?

For a reaction to proceed