Can someone help me with this problem?

A new super antacid was just released onto the market. A single tablet weighing .3541 g was added to 25 ml of .981 M HCl. The acid that remained after the tablet had reacted required 10.31 ml of .183 M Ca(OH)2. How many moles of acid was neutralized by the tablet?

The equation given is:

HCl (aq) +NAOH (aq) produces NaCl + H2O

all about using moles

total moles acid gets used up by 1) reaction with antacid and 2) reaction of leftover acid with hydroxide.

you should be able to determine the moles of hydroxide used from the molarity and volume of Ca(OH)2. Hint: how many hydroxides can one mole of Ca(OH)2 provide?

Then you know from the equation how many moles of acid were left over to react.

You know the total number of moles of acid from, again, molarity and volume... so its simple... total moles acid - moles acid left = moles acid consumed by antacid.