Chapter 5, Problem 5.26AP

Which of the following equations are balanced? Balance those that need it.

(a)     $2{\text{C}}_{\text{2}}{\text{H}}_{\text{6}}\left(g\right)+5{\text{O}}_{\text{2}}\left(g\right)\to 2{\text{CO}}_{\text{2}}\left(g\right)+6{\text{H}}_{\text{2}}\text{O}\left(l\right)$

(b)     $3\text{Ca}{\left(\text{OH}\right)}_{\text{2}}\left(aq\right)+2{\text{H}}_{\text{3}}{\text{PO}}_{\text{4}}\left(aq\right)\to {\text{Ca}}_{\text{3}}{\left({\text{PO}}_4\right)}_{\text{2}}\left(aq\right)+6{\text{H}}_{\text{2}}\text{O}\left(l\right)$

(c)     $\text{Mg}\left(s\right)+{\text{O}}_{\text{2}}\left(g\right)\to 2\text{MgO}\left(s\right)$

(d)     $\text{K}\left(s\right)+{\text{H}}_{\text{2}}\text{O}\left(l\right)\to \text{KOH}\left(aq\right)+{\text{H}}_{\text{2}}\left(g\right)$