By definition, #"concentration"="amount of SOLUTE"/"amount of solution"#...and normally we use units of #mol*L^-1# or #g*L^-1#... Here we probably should first find the concentration of the mother solution in #mol*L^-1#...and so...working from a #1*mL# volume...
#[HCl(aq)]=((1*mLxx1.179*g*mL^-1xx36%)/(36.46*g*mol^-1))/(1*mLxx10^-3*L*mL^-1)=11.64*mol*L^-1#...this is concentrated stuff...the conc, #HCl# we use in the lab is #10.6*mol*L^-1#.
And we want #5.10*L# of a solution whose #pH=1.7#... Now, by definition...#pH=-log_10[H_3O^+]#...i.e. #[H_3O^+]=10^(-1.7)*mol*L^-1=0.0200*mol*L^-1#...and so...
#"moles of HCl required"-=5.10*Lxx0.0200*mol*L^-1=0.102*mol#..
#"Volume of conc. acid"=(0.102*mol)/(11.64*mol*L^-1)=0.00874*L#, i.e. #8.70*mL#.
And #"YOU MUST ADD ACID TO WATER"# and never the #"REVERSE"#. Why not? Because if you spit in concentrated acid, it spits back. I kid you not....