If you avoid doing a bronsted acid-base reaction initially, there is only one reaction sequence which uses all 4 reagents/conditions that will lead to an alkyne product starting from the ethyl benzene as your organic reactant.

i wish i could but this one is weird give me abc and i can solve it.

the maximum mass of nh3 is nh3 in grams

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.

yes the answer is total mass in unchanged   : )