1) It's written that it should be in alcoholic solution. Where is it indicated in the equation ?!.. 2) The H+ written on the arrow is written to avoid writing dil. HCl or H2SO4 ?!.. 3) Below the arrow in the second point, is it pressure or atoms only ?!.. [Kindly answer 3 of these here, as these are very short answers and related to the same image, same topic.]
I) Alcoholic solution is needed to dissolve the sucrose as like dissolves like and sucrose cannot be dissolved in water but can be done in alcohol.
II) H+ is written to avoid writing of HCl or H2SO4 as they are added to provide H+ ions.
III) It is 2-3 atm (pressure).