What volume of 0.200 M AgNO3 is required to produce 0.250 g Ag solid?​

Iknow the answer to 13 is b and 14 is d. i just need to know why the correct answers are correct

Which statement is true about a catalyst? a: a catalyst decreases the rate of the reaction. b. a catalyst is consumed during a chemical reaction. c. a catalyst lowers the activation energy of a reaction. d. a catalyst increases the reactant concentration during a reaction.

What is the solubility-product constant of barium sulfate, baso4, if a saturated solution is 1.03 ´ 10-5 m?