题目

(6分)写出除杂反应方程式(括号内的物质为杂质)。(1)FeSO4(CuSO4)________________________________________________(2)CaO(CaCO3) _______________________________________________(3)NaOH(Na2CO3)______________________________________________(4)HNO3 (HCl) _______________________________________________(5)KNO3(K2SO4)_______________________________________________(6)NaCl (NH4Cl) ______________________________________________­_ 7．设0＜x＜$\frac{π}{2}$，记a=sinx，b=x，c=lnsinx，试比较a，b，c的大小关系为（　　）A．a＞b＞cB．a＞c＞bC．b＞a＞cD．b＞c＞a