解：设该孔雀石中$Cu_{2}(OH)_{2}CO_{3}$的质量为$x。$
$Cu_{2}(OH)_{2}CO_{3}+2H_{2}SO_{4}=CO_{2}\uparrow + 2CuSO_{4}+3H_{2}O$
$222$ $44$
$x$ $4.4\ g$
$\frac{222}{44}=\frac{x}{4.4\ g}$， $x = 22.2\ g$
该孔雀石中$Cu_{2}(OH)_{2}CO_{3}$的质量分数为
$\frac{22.2\ g}{25\ g}×100\% = 88.8\%$
答：该孔雀石中$Cu_{2}(OH)_{2}CO_{3}$的质量分数为$88.8\%。$
