For the first one the answer is B. and the second one is D.
Multiple states of matter - mixture
Same state of matter - pure
Separated physically- mixture
Consistent properties - pure
Can’t be separated- pure
Can’t be a single element - mixture
Hydrochloric acid ionisation is as follows;
HCl ---> H⁺ + Cl⁻
HCl is a strong base so there's complete dissociation of acid to H⁺ ions
The number of HCl moles is equivalent to number of H⁺ ions present
1 L of solution contains - 11.6 moles of H⁺ ions
In 35 ml number of moles - 11.6 mol/L / 1000 ml x 35 ml = 0.406 mol
This number of moles are dissolved in 500 ml
therefore molarity = 0.406 mol /500 ml x 1000 ml = 0.812 M
