A solvent is something that can have something else dissolved within it and turn into a homogenous solution, while the solute is that something else that can be dissolved into the solvent. Usually, the solvent is found in greater amount because most (except for rare cases) solvents have a saturation point that is below the equal-mass point.
M(NaOH)=15 g
v=600 ml=0.6 l
n(NaOH)=m(NaOH)/M(NaOH)
C=n(NaOH)/v=m(NaOH)/[M(NaOH)v]
C=15g/[40g/mol*0.6 l]=0.625 mol/l
0.625M
[H⁺]=7.5*10⁻²
pOH=14-pH=14+lg[H⁺]
pOH=14+lg(7.5*10⁻²)=14-1.125=12.875
The answer is D because, hope this helps
0.007 - ?micrograms
0.007= 700micrograms
multiply the mass value by 100000