Question

Why the cinemas always be added slowly to water with constant sharing?

Answer 1

Water solution contains 50% na2s2o2 together with 1% soluble impurity. upon cooling to 10°c, na2s2o2· 5h2o crystallizes out. the solubility of this hydrate is 1.5 lb na2s2o2· 5h2o per lb free water. the crystals removed carry as adhering solution 0.06 lb solution per lb crystals. when dried to remove the remaining water (but not the water of hydration), the final dry na2s2o2· 5h2o crystals must not contain more than 0.1% impurity. to meet this specification, the original solution, before cooling, is further diluted with water. on the basis of 200 lb of the original solution, calculate