What is the molarity of an HCl solution if 50.0 mL is neutralized in a titration by 40.0 mL of 0.4000 M NaOH? a 0.20 M b 0.50 M c 0.32 M d 0.20 M

Convection is da answer my dood

A. is your answer.  hope this  

Radon-222 or rn-222 has a half-life of 3.82 days. to determine the fraction of an original sample of rn-222 that remains unchanged after 7.646 days, we calculate the amount of rn-222 remaining after 7.646 days and divide it with the original amount. using 1 gram as a basis and using half-life calculation methods, we can determine that  0.249 or 0.25  grams of rn-222 will remain, and thus the fraction remaining is 0.25 or 1/4.