Q. No. 1:
 a) Endothermic
 b) Exothermic
 c) Endothermic
 d) Exothermic
Q. No. 2:
 a) Exothermic
 b) Because heat is on product side (evolved to surrounding).
 c) 
 
 1400 Kj = was produced by 1 mole of C₂H₄
Then,
 2100 Kj = will be produced by X moles of C₂H₄
Solving for X,
 X = (2100 Kj × 1 mol) ÷ 1400 Kj
 X = 1.5 moles of C₂H₄
 d)
 3 moles of O₂ produced = 1400 Kj of Heat
Then,
 1.5 moles of O₂ will produce = X Kj of Heat
Solving for X,
 X = (1.5 mol × 1400 Kj) ÷3 mol
 X = 700 Kj of Heat