Question

A student dropped a few pieces of marble in dilute hydrochloric acid, contained in a test-tube. The evolved gas was then passed through lime water. What change would be observed in lime water?
What will happen if an excess of gas is passed through lime water? With the help of balanced chemical equations for all the changes explain the observations.

Answer 1

Hint: For dealing with this question we will first see the definition of marble, chemical equations of marble, lime water and then then we will further see the chemical reactions occurring with the equations.

Complete answer:
Chemically, marble is known as calcium carbonate. When calcium carbonate is reacted with HCl, the product formed is Calcium chloride and the by products are water and carbon dioxide. The chemical equation is as
\[CaC{O_3} + 2HCl \to CaC{l_2} + {H_2}O + C{O_2}\]
As we know the reaction between carbon dioxide and lime water. When lime water reacts with carbon dioxide it turns lime water milky. The reaction is shown below.
$Ca{\left( {OH} \right)_2} + C{O_2} \to CaC{O_3} + {H_2}O$
Additional information - Gasses that can capture heat are greenhouse gasses. From the greenhouses they get their name. A greenhouse is lined with sunshine screens. A greenhouse's main trick is that it doesn't allow the energy to escape. The sunshine provides warmth. A greenhouse's main trick is that it doesn't allow the energy to escape. This is how greenhouse gasses work. They allow sunshine to pass into the atmosphere, but stop the heat from the atmosphere generated by light. Other than that, a positive thing about greenhouse gasses is our world would be too cold without them, so we wouldn't survive as we do. Scientists are afraid that these emissions are very frequently applied to the atmosphere by human actions.

Note:
Lime water turns milky due to formation of ppt of \[CaC{O_3}\] on passing excess of $C{O_2}$ The milkiness of the lime water disappear after the formation of $Ca{\left( {HC{O_3}} \right)_2}$ which is soluble in water. The reaction is given below
\[CaC{O_3} + {H_2}O + C{O_2} \to Ca{\left( {HC{O_3}} \right)_2}\]