题目

I first came across the concept of pay-what-you-can cafes last summer in Boone, N.C., where I ate at F.A.R.M (Feed All Regardless of Means) Café. You can volunteer to earn your meal, pay the suggested price($10) or less, or you can overpay—paying it forward for a future customer’s meal. My only regret after eating there was not having a chance to give my time. So as soon as Healthy World Café opened in York in April, I signed up for a volunteer shift(轮班). F.A.R.M and Healthy World are part of a growing trend of community cafés. In 2003, Denise Cerreta opened the first in Sal用含钴废料(主要成分为Co，含有一定量的Ni、Al2O3、Fe、SiO2等)制备草酸钴晶体(CoC2O4·2H2O)的工业流程如图。已知：①草酸钴晶体难溶于水；②RH为有机物(难电离)。(1)H2O2是一种绿色氧化剂，写出加入H2O2后发生反应的离子方程式：_________________。(2)加入氧化钴的目的是_______________________________。(3)草酸钴晶体分解后可以得到多种钴的氧化物(其中Co的化合价为＋2、＋3)，取一定量钴的氧化物，用280mL5mol·L－1盐酸恰好完全溶解，并得到CoCl2溶液和2.24L(标准状况)黄绿色气体，由此可确定该钴氧化物中Co、O的物质的量之比为________。(4)实验室可以用酸性KMnO4标准液滴定草酸根离子(C2O42-)，测定溶液中的浓度，写出此反应的离子方程式：_______________________________________；KMnO4标准溶液常用硫酸酸化，若用盐酸酸化，会使测定结果________(填“偏高”“偏低”或“无影响”)。