Question

Which of the following is a single replacement reaction?

2Al + 6H2O 2Al(OH)3 + 3H2

CH4 + 2O2 CO2 + 2H2O

Fe2O3 + 3H2O 2Fe(OH)3

AgNO3 + NaCl AgCl + NaNO3

Answer 1

i think it is:
2Al + 6H2O 2Al(OH)3 + 3H2

Answer 2

I would agree with Kryten.

If you look at each of your reactions~ the first is the only reaction where ONLY ONE element (Hydroxide I believe) is switching places (which is the definiton of a single replacement).

The second reaction looks like a double replacement, the third looks like a combination (synthesis) and the last looks to be a double replacement also.