Tag: chemistry

Metal carbonate or metal hydrogen carbonate and acid are used in fire extinguisher to produce carbon dioxide gas. Acid and metal carbonate or bicarbonate are kept in separate chambers in a fire extinguisher. On emergency, they are allowed to react with one another. The carbon dioxide gas so produced is poured over fire. As carbon dioxide does not support burning, it puts off the fire.

Using sulphuric acid and calcium carbonate, you don't get much of a fizz because the calcium sulphate salt formed, is not very soluble, and coats the remaining calcium carbonate inhibiting the reaction. This will happen with any reaction between an acid and a water insoluble reactant which forms an insoluble solid product.

On adding a hydrogen carbonate to an acid, effervescence from carbon dioxide gas is released along with the formation of water and salt. $CO _2$ turns lime water milky.
$ NaHCO _3 + HNO _3 \rightarrow NaNO _3 + H _2O + CO _2 $

On adding a carbonate to an acid, effervescence from carbon dioxide gas is released along with the formation of water and salt. $CO _2$ turns lime water milky.
Phosphoric acid + sodium carbonate $\rightarrow$ sodium phosphate + water + carbon dioxide
$ 2H _3PO _4 + 3Na _2CO _3 \rightarrow 2Na _3PO _4 + 3H _2O + 3CO _2 $

Crushed egg shell has composition $CaCO _3$ reacts with acid and gives gas $CO _2$ which turns lime water $(Ca(OH) _2)$ milky by producing $CaCO _3$ again. The acid in given options is $HCl$. 

When $HCl$ reacts with sodium hydrogen carbonate, the products obtained are $NaCl,$ $H _2O$ and $CO _2$.
$\displaystyle NaHCO _3 + HCl \rightarrow NaCl + H _2O + CO _2$

When $HCl$ reacts with calcium carbonate, the products obtained are $CaCl _2$, $H _2O$ and $CO _2$.
$\displaystyle CaCO _3 + 2HCl \rightarrow CaCl _2 + H _2O + CO _2$

Acid + Metal carbonate  $\longrightarrow$ Salt + Water + Carbon dioxide

CaCO$ _3$ (calcium carbonate-metal carbonate) + 2HCl $\longrightarrow$ CaCl$ _2$ (calcium chloride-salt) + H$ _2$O + CO$ _2$

Another form of solid carbon dioxide observed at high pressure is an amorphous glass-like solid. This form of glass, called carbonia, is produced by supercooling heated $C{O} _{2}$ at extreme pressure ($40 48  GPa$ or about $400,000$ atmospheres) in a diamond anvil.
This discovery confirmed the theory that carbon dioxide could exist in a glass state similar to other members of its elemental family, like silicon (silica glass) and germanium dioxide.