Answer
a) 2Na(s) + 2H$_{2}$O(l) --> 2NaOH(aq) + H$_{2}$(g)
b) Ca(s) + 2H$_{2}$O(l) --> Ca(OH)$_{2}$(aq) + H$_{2}$(g)
Work Step by Step
a) 2Na(s) + 2H$_{2}$O(l) --> 2NaOH(aq) + H$_{2}$(g)
b) Ca(s) + 2H$_{2}$O(l) --> Ca(OH)$_{2}$(aq) + H$_{2}$(g)