Of the reactions below, which one is a double-replacement reaction?

a. nh4cl -> nh3 + hcl
b. 2 mg + o2 -> 2 mgo
c. 2 n2 + 3 h2 -> 2 nh3
d. cd(no3)2 + na2s -> cds + 2 nano3

At 40 âc the solution has at 40 â c the solution has blank g of k n o 3 per 100 g of water and it can contain up to blank g of k n o 3 per 100 g of water. at 0 â c the solubility is ~ blank g k n o 3 per 100 g of water, so ~ blank g k n o 3 per 100 g of water will precipitate out of solution. g of kno3 per 100 g of water and it can contain up to at 40 â c the solution has blank g of k n o 3 per 100 g of water and it can contain up to blank g of k n o 3 per 100 g of water. at 0 â c the solubility is ~ blank g k n o 3 per 100 g of water, so ~ blank g k n o 3 per 100 g of water will precipitate out of solution. g of kno3 per 100 g of water. at 0 âc the solubility is ~ at 40 â c the solution has blank g of k n o 3 per 100 g of water and it can contain up to blank g of k n o 3 per 100 g of water. at 0 â c the solubility is ~ blank g k n o 3 per 100 g of water, so ~ blank g k n o 3 per 100 g of water will precipitate out of solution. kno3 per 100 g of water, so ~ at 40 â c the solution has blank g of k n o 3 per 100 g of water and it can contain up to blank g of k n o 3 per 100 g of water. at 0 â c the solubility is ~ blank g k n o 3 per 100 g of water, so ~ blank g k n o 3 per 100 g of water will precipitate out of solution. gkno3 per 100 g of water will precipitate out of solution. a kno3 solution containing 55 g of kno3 per 100.0 g of water is cooled from 40 ∘c to 0 ∘c. what will happen during cooling?

Consider the nuclear equation below. 239/94 pu—-> x+ 4/2 he. what is x?

Ineed to find the answer of this question because i dont understand it