Which formula equation shows a reversible reaction? 2 Upper N a + Upper F Subscript 2 Baseline right arrow 2 Upper N a Upper F. Upper C a Upper C Upper O Subscript 3 Baseline right arrow Upper C a Upper O + Upper C Upper O Subscript 2. Upper N Upper H Subscript 4 Baseline Upper C l (s) double-pointed arrow Upper N Upper H Subscript 3 Baseline (g) + Upper H Upper C l (g). 2 Upper H Subscript 2 Baseline Upper O Subscript 2 Baseline (a q) right arrow with n above it 2 Upper H Subscript 2 Baseline Upper O (l) + Upper O Subscript 2 Baseline (g).