First, we need to know that 6M means 6 mol/L.
So, we have 6 mol of KOH in 1 liter of solution.
To know the amount in grams, we need to use the following formula:
mass = moles x molar mass of KOH
molar mass of KOH is 56.1056 g/mol.
So:
56.1056 g--- 1 mol
x g --- 6 mol
x = 336.6 g
Answer: There are 336.6 g of solute.