Question

how many grams of HCl will be needed to react completely with a solution containing 15 grams of NaOH?​

Answer 1

4 gram of NaOH is 0.1 moles.

To neutralize 0.1 moles of base, you need 0.1 moles of acid.

0.1 moles of HCl is 3.65g of HCl. To account for your acid dilution, you need 3.65/0.15 or 24.3g of 15% HCl to neutralize 4g of 100% NaOH.

I apologize if any of my numbers were wrong, didn't look through a periodic table on account of doing it on my phone but you get the method