If 17.7 mL of 0.800 M HCl solution are needed to neutralize 5.00 mL of a household ammonia solution what is the molar concentration of the ammonia?

0,800 M HCl

= 0,800 moles per 1000 ml (1L)

= 0,0148 moles per 18,5 ml

So you also need 0,0148 moles ammonia to neutralize.

= 0,0148 Moles per 5 ml

= 2,96 Moles per 1000 ml (1L)

So the answer= 2,96 M