Question

Which of the following is a single replacement reaction?

2Al + 6H2O yields 2Al(OH)3 + 3H2
AgNO3 + NaCl yields AgCl + NaNO3
Fe2O3 + 3H2O yields 2Fe(OH)3
CH4 + 2O2 yields CO2 + 2H2O

Answer 1

The answer is the first one. 2Al+6H2O yields 2Al(OH)3H2

Answer 2

2Al +H2O yield 2Al(OH)3 + 3H2 (answer A)

is an example of single replacement reaction

This is because single replacement reaction involve an element reacting with a compound and take place of another element in that compound. Al an element react with to yield Al(OH)3 and H2. Al take place of H + therefore the reaction above is example of single replacement.