What did I do wrong in this chemistry problem? (Pls explain how to get the correct answer if possible)

Which substances have the lowest melting points: ionic covalent, or metallic

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.

Complete the following statements to describe solids, liquids, and gases. select the correct answer from each drop-down menu. a solid a definite volume and a definite shape. a liquid a definite volume and a definite shape. a gas a definite volume and a definite shape