题目

  Psychology has a new application in the field of medicine. Many doctors, together with their patients, are looking for alternative methods of treatment of physical problems. In large hospitals, modern therapy（疗法） seems to focus on the physical disease. Patients may feel they are treated like broken machines. Some doctors have recognized this as a problem. They are now using psychological therapy, in which the patient is working with the doctors against the disease with the help of medicine. The patient does not wait for the medicine and treatment to cure him or her, but inst连二次硝酸(H2N2O2)是一种二元酸，可用于制N2O气体。（1）常温下，用0.01mol·L-1的NaOH溶液滴定10mL0.01mol·L-1H2N2O2溶液，测得溶液pH与NaOH溶液体积的关系如图所示。①写出H2N2O2在水溶液中的电离方程式：__。②c点时溶液中各离子浓度由大到小的顺序为__。③b点时溶液中c(H2N2O2)__c(N2O22-)。(填“＞”“＜”或“=”，下同)④a点时溶液中c(Na+)__c(HN2O)+c(N2O22-)。（2）硝酸银溶液和连二次硝酸钠溶液混合，可以得到黄色的连二次硝酸银沉淀，向该分散系中滴加硫酸钠溶液，当白色沉淀和黄色沉淀共存时，分散系中=__。[已知Ksp(Ag2N2O2)=4.2×10-9，Ksp(Ag2SO4)=1.4×10-5]（3）有时我们将NaHCO3溶液中的平衡表示为：2HCO3-H2CO3+CO32-；为了证明该平衡存在，你认为应向NaHCO3溶液中加入下列哪种试剂合理___（填序号）A.适当浓度的盐酸B.适当浓度Ba(OH）2溶液C.适当浓度BaCl2溶液