(2) Potassium carbonate

(3) CD

(4) Chlorine-

(5) There is colorless gas and white precipitate in 2mno2+2e-+H2O = 2oh-+Mn2O3.

Test and analysis: (1)K 2 CO 3 solution absorbs CO 2 to generate KHCO 3, and K+ is deleted and written as ionic equation.

(2)KHCO 3 is decomposed by heat, and K 2 CO 3 is obtained, which is a circulating substance;

(3) There are two characteristics when the reaction reaches equilibrium: one is that V (positive) = v (negative); Second, the content of each substance component remains unchanged. An image does not indicate the rate of reverse reaction, so it cannot be determined; B is the equilibrium constant k, which has nothing to do with whether the reaction reaches equilibrium or not, but is related to temperature, and B cannot judge whether it is equilibrium or not; The amounts of CH 3 OH and CO 2 in c remain unchanged, that is, the composition remains unchanged, indicating that the equilibrium state has been obtained; D means that the content fraction and composition of H 2 remain unchanged, which means that equilibrium is reached.

(4)0.0 1mol/L Cl-, when the precipitation starts, c (ag+) =1.56×10-8; 0.0 1mol/L CrO 4 2-, and c(Ag+)= =3.0× 10 -5 at the beginning of precipitation. Therefore, Cl- precipitates first.

(5) Oxidizer MnO _ 2 is used as cathode material to obtain electrons and generate Mn 2 O 3. Pay attention to the environment, so OH- is generated. Electrolyze (inert electrode) the fully mixed solution of Mg(NO 3) 2 and NaCl. According to the discharge sequence, the anode Cl- discharges and the cathode H+ discharges, resulting in OH-, and the combination of OH- and Mg 2+ produces a white precipitate of Mg(OH) 2. Sp calculation and electrochemical reaction principle.