Answer
pH=1.8
Work Step by Step
CF3SO3H(aq)+H2O(l)-->H+(aq)+CF3SO3H(aq)
V(CF3SO3H)=250mL=0.25L
m(CF3SO3H)=0.616g
pH(CF3SO3H)=?
n(CF3SO3H)=m(CF3SO3H)$\div$M(CF3SO3H)
=0.616g$\div$(12+3$\times$19+32.06+3$\times$16+1.008)$\frac{g}{mol}$
=0.0041 mol
c(CF3SO3H)= n(CF3SO3H)$\div$V(CF3SO3H)
=0.0041mol$\div$0.25L
=0.016$\frac{mol}{L}$
c(CF3SO3H)=c(H+)=0.016$\frac{mol}{L}$
pH=-log c(H+)
pH=-log(0.016)
pH=1.8
