题目

 We visited the factory ______ makes toys for children. A. where            B. which           C. in which            D. at which 答案：B下列离子方程式书写正确的是 ( )A. 将0.2mol/L的NH4Al(SO4)2溶液与0.3mol/L的Ba(OH)2溶液等体积混合：2Al3++3SO42 ─+3Ba2++6OH ─= 2Al(OH)3↓+3BaSO4↓B. 硫氢化钠的水解反应： HS ─+ H2O S2 ─+ H3O+C. 铁片放入过量的稀硝酸中：3Fe＋8H＋＋2NO3 ─ = 3Fe2＋＋2NO↑＋4H2OD. 酸性高锰酸钾可使草酸溶液褪色：2MnO4 ─＋5C2O42 ─＋16H＋ = 2Mn2＋＋10CO2↑＋8H2O