Answer:
B) H2SO4 (aq) + Ca(OH)2 (aq) → CaSO4 (aq) + 2 H2O(l)
Explanation:
A is a reaction between a salt FeCl3 and a base KOH
C is a n acid decomposing on it's own to form two products
D is mercury, a metal reacting with oxygen. Two elements reacting. Neither are an acid or a base
E. is an acid reacting with a metal to liberate hydrogen. There is no base
It will be number 1.
NO loses oxygen ie its being reduced to N2
NH3 gains oxygen atom ie its being oxidised to H2O
D. the student's conclusion shows experimental bias