The four test tubes contain the following crystalline substances: sodium sulfate, ammonium chloride

The four test tubes contain the following crystalline substances: sodium sulfate, ammonium chloride and sodium nitrate. Determine which test tubes each of these substances is in.

We have sodium sulfate in the test tube. To begin with, we take three tubes and dissolve a little salt in each tube, respectively. And we add barium nitrate or chloride to each. A milky precipitate will appear in the tube with sodium sulfate, the tube will turn cloudy white. In all the rest there will be nothing. We take two more test tubes, and as before we dissolve the remaining salts. Add silver nitrate. In a test tube with ammonium chloride, a curd white precipitate of silver chloride falls out. The last tube is sodium nitrate.