When ag water is evaporated from a salt solution at constant temperature, bg crystal without crystal water precipitates, and cg crystal without crystal water precipitates after ag water is evaporated, the mass fraction of solute in the original solution is () A.100(b+c) 2A+b+c% B.b+c 2A+b+c% C.100c A + c% D. Unable to determine When ag water is evaporated from a salt solution at constant temperature, bg crystal without crystal water precipitates, and cg crystal without crystal water precipitates after ag water is evaporated, the mass fraction of solute in the original solution is () A.100(b+c) 2A+b+c% B.b+c 2A+b+c% C.100c A + c% D. Not sure

When ag water is evaporated from a salt solution at constant temperature, bg crystal without crystal water precipitates, and cg crystal without crystal water precipitates after ag water is evaporated, the mass fraction of solute in the original solution is () A.100(b+c) 2A+b+c% B.b+c 2A+b+c% C.100c A + c% D. Unable to determine When ag water is evaporated from a salt solution at constant temperature, bg crystal without crystal water precipitates, and cg crystal without crystal water precipitates after ag water is evaporated, the mass fraction of solute in the original solution is () A.100(b+c) 2A+b+c% B.b+c 2A+b+c% C.100c A + c% D. Not sure

After the ag water is evaporated, cg crystal without crystal water is precipitated, so the mass fraction of solute in the saturated solution can be calculated; since the problem does not tell the mass of the original solution, the mass fraction of solute in the original solution can not be calculated, so D is correct.
Therefore, D.

Why the solubility of AgCl in NaCl solution first decreases and then increases

Does it refer to the increase of chloride ion concentration? When the concentration of chloride ion increases, the complexation reaction of silver chloride produces [AgCl2]-ion, which is the complexation effect in precipitation solution equilibrium.