The number of moles of solute in a bottle containing 300 mL of 0.178 mol/L sodium sulfite solution is

0.178 * 300/1000

To calculate the number of moles of solute in a solution, you need to use the equation:

moles of solute = (concentration of solution) x (volume of solution in liters)

Given that the concentration of the sodium sulfite solution is 0.178 mol/L and the volume of the solution is 300 mL, you need to convert mL to L by dividing by 1000:

volume of solution = 300 mL ÷ 1000 = 0.3 L

Now you can plug the values into the equation:

moles of solute = 0.178 mol/L x 0.3 L = 0.0534 moles

Therefore, the number of moles of sodium sulfite in the 300 mL solution is 0.0534 moles.