# Question #78c3c

Feb 19, 2017

There's not enough data to identify M. It could be any of the group 1 metals (except maybe Lithium). Let's keep calling it M.

#### Explanation:

Burning in air:
$4 M + {O}_{2} \to 2 {M}_{2} O$ so $X = {M}_{2} O$

X reacting with water:
${M}_{2} O + {H}_{2} O \to 2 M O H$ so $Y = M O H$

M reacting with water:
$2 M + 2 {H}_{2} O \to 2 M O H + {H}_{2}$ so $Z = {H}_{2}$

Y being heated:
$2 M O H \to {M}_{2} O + {H}_{2} O$