Iodine can be prepared by bubbling chlorine gas through an aqueous solution of sodium iodide:

Question

2NaI(aq) + Cl2(g) → I2(s) + 2NaCl(aq)

How many grams of sodium iodide are required to produce 98 g of iodine?

Answer 1

mols I2 = grams/molar mass
Use the coefficients to convert mols I2 to mols NaI. 2 mols NaI = 1 mol I2; therefore mols NaI = 2x mols I2.
grams NaI = mols NaI x molar mass NaI.