To generate a carbene, sodium hydroxide is reacted with dichloromethane. Since both have extremely low solubility in the same solvents a chemical was used to increase their interaction. What was the name of that chemical

Asample of hydrated tin (ii) chloride (sncl2) has a mass of 4.90 g. when it is dehydrated, it has a mass of 4.10 g. which is the correct chemical formula for the hydrate? sncl2•2h2o          sncl2•4h2o          sncl2•6h2o

What is a number added in front of a formula in order to balance the equation

If the theoretical yield of a reaction is 26.0 grams and you actually recovered 22.0 grams, what is the percent yield?