Please help with numbers 2&3

Which compound contains both ionic and covalent bonds? a) hbr b)cbr4 c)nabr d) naoh

Achemistry student weighs out 0.306 g of citric acid (h3c6h5o7), a triprotic acid, into a 250 ml volumetric flask and dilutes to the mark with distilled water. he plans to titrate the acid with 0.1000 m naoh solution. calculate the volume of naoh solution the student will need to add to reach the final equivalence point. be sure your answer has the correct number of significant digits.

If a solution contains 3 moles/liter of sodium chloride (nacl, made of sodium ions and chloride ions), what is the osmolarity of this solution