What is the product of the reaction of carbon with sulfuric acid?
Carbon reacts with sulfuric acid to produce carbon dioxide and sulfur dioxide gas along with water. Sulfuric acid should be a concentrated, heated solution.

$$\ce{C + 2H2SO4 -&gt;[\Delta] CO2 + 2SO2 + 2H2O}$$

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Copper(II) oxide, a black solid, and dilute sulfuric acid react to produce copper(II) sulfate, giving a characteristic blue colour to the solution. From this solution, blue copper(II) sulfate pentahydrate crystals may be obtained if desired.

$$\ce{CuO + H2SO4⟶CuSO4↓+H2O}$$

It is a general "insoluble metal oxide is reacted with a dilute acid to form a soluble salt" type of reaction. It is a standard class experiment.

More insight about this reaction can be found here.