How many moles of nitrogen dioxide are required to produce 3.56 moles of nitric acid?

Iknow #2 is d. i just need to know why

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.

Draw a line graph showing the relationship between temperature in kelvin as a function of kinetic energy.