The equivalence point in a titration refers to the point when the mL of the acid equals the mL of the base.
the molarity of the acid used in the reaction equals the molarity of the base used in the reaction.
the number of moles of one reactant reacts completely with the moles of the other reactant.
the acid in the flask turns clear.

they both have a y in them

first one is the correct answer

when the volume of gas is   changed from   717.73 ml   to 852 ml   the temperature will   change   from 315   c to 452   c

    calculation

this is calculated using the charles law formula

that is,   v1/t1 = v2/t2

          v1=?

        t1 = 315 c   into   kelvin = 315 +273 = 588 k

        v2 = 852   ml

        t2 = 425c + 273 =698 k

make v1   the subject of the formula ( by   multiplying both side by t1)

  v1=( v2 xt1) / t2

v1= (852 ml   x 588 k)/ 698 k= 717.73 ml