Question

Take a teaspoonful of washing soda in the given glass. Light the candle in the spoon and put it in the same glass. Add $10$ to $20$ drop of given solution into the washing soda. Observe what happens and answer the following questions.
$Q1$ . What happens when a given solution is added to the washing soda?
$Q2$ . What is the effect on lighted candles after some time?
$Q3$ . From above two observations, identify which gas is formed?
$Q4$ . In which device, the above reaction is used?
$Q5$ . What type of solution is used in this experiment? Choose from below: (Acid/Salt/Base)

Answer 1

Washing soda is the combination of several hydrated forms of sodium carbonate. It is usually expressed as$N{a_2}C{O_3}.x{H_2}O$ . Lighting a candle generates heat energy.

Complete step by step answer: The given question is a type of experimental evidence for a phenomena called dehydration. The washing soda which we use daily for cleaning purposes is the hydrated form of Na2CO3. If washing soda is heated using the heat from lighted candles the chemical composition changes. The answer to the given question lies in the observation of the dehydration process.
Answer$1$) When the given solution is added to washing soda a molecule of sodium carbonate is generated. It is freed from the absorbed water molecule.
$N{a_2}C{O_3}\xrightarrow{{Candle{\text{ }}light}}N{a_2}C{O_3} + x{H_2}O$
Answer$2$) The lighted candle undergoes complete combustion to produce steam and carbon dioxide. It is a type of reaction between wax and oxygen.
Answer$3$) The gas formed from both the processes is carbon dioxide. The reaction is shown as:
$N{a_2}C{O_3} \to N{a_2}O + C{O_2} \uparrow$
Answer$4$) The above reaction is used in petri dishes.
Answer$5$) Sodium carbonate is a salt formed of sodium cation and carbonate anion. So the solution used in this experiment is a salt.

Note: The carbonates of alkali and alkaline earth are thermally unstable. They undergo thermal decomposition when allowed to come in contact with heat.