Need help with this Pre-AP Chemistry problem. I’m not sure which reactions were oxidized/reduced. Answer 4 wasn’t correct.

Need help with this PreAP Chemistry problem Im not sure which reactions were oxidizedreduced Answer 4 wasnt correct class=

Respuesta :

Catya
I remember the acronym: OIL RIG
Oxidation is Loss
Reduction is Gain

Reaction side (LEFT) oxidation numbers
Magnesium = +2 
Oxygen = -2
Product side (RIGHT) oxidation numbers
Mg = 0
Oxygen = 0
Mg gained -2e = reduction

Only answer is #2