chemistry 的問題

When heated, concentrated sulphuric acid reacts withcarbon. This is a redox reaction, in which the concentrated sulphuric acid isreduced to sulphur dioxide, while carbon is oxidized to carbon dioxide. Theequation is:
C + 2H2SO4 → 2H2O + 2SO2 + CO2

When heated, concentrated nitric acid reacts with carbon. This is also a redoxreaction, in which the concentrated nitric acid is reduced to nitrogen dioxide,while carbon is oxidized to carbon dioxide. The equation is:
C + 4HNO3 → 2H2O + 4NO2 + CO2

2011-05-19 21:30:27 補充：
The carbon used in the above equation is carbon powder (charcoal powder).

"graphite can make electrodes" doesn't mean that it's ALWAYS inert to EVERY chemicals.
in fact, graphite is sometimes NOT recommended being used in half-cell producing oxygen, as O2 can attack carbon to give CO2 ----> contamination.

Even carbon is inert element. It still can be oxidized by strong oxidizing agents like conc sulphuric acid or conc nitric acid.

Carbon 有好多種存在方式，相信你問的應該不外乎 graphite 同 diamond.

Graphite 可以用作 electrode, 所以同 conc. sulfuric acid 或者 conc. nitric acid 之間都沒有 redox reaciton.
所以 conc. sulfuric acid + carbon 沒有 chemical equation.

但 conc. nitric acid 本身會 decompose, 所以有 equation, 但 carbon 只是 spectator, 不在 equation 之內，equation for decompsition of nitric acid:

4 HNO3 → 4 NO2 + 2 H2O + O2