Why does only dilute nitric acid react with dry sodium carbonate?
When sodium bicarbonate reacts with nitric acid, sodium nitrate salt is formed along with carbonic acid (double replacement reaction), which immediately decomposes to water and gaseous carbon dioxide (which explains the fizzing). The concentration of the nitric acid affects the rate of reaction, the more dilute it is, the slower the reaction will progress. The more pure the nitric acid, the faster the reaction will take place.
