if a moist blue litmus paper is brought near co2 gas
If a moist blue litmus paper is brought near CO₂ gas…
Answer:
When moist blue litmus paper is brought near CO₂ gas, a chemical reaction occurs that leads to a noticeable change in the color of the litmus paper. Let me explain the process step-by-step for clarity.
Solution By Steps:
-
CO₂ Dissolution in Water:
-
When CO₂ gas comes into contact with the water present on the moist blue litmus paper, it dissolves in the water.
-
This dissolution can be represented by the following chemical equation:
CO_2 + H_2O \rightarrow H_2CO_3 -
Here, CO_2 (carbon dioxide) reacts with H_2O (water) to form carbonic acid (H_2CO_3).
-
-
Formation of Carbonic Acid:
-
Carbonic acid (H_2CO_3) is a weak acid but it does contribute to the acidity of the solution.
-
The carbonic acid dissociates partially in water to form hydrogen ions (H^+) and bicarbonate ions (HCO_3^-):
H_2CO_3 \leftrightarrow H^+ + HCO_3^- -
This reaction increases the concentration of hydrogen ions (H^+) in the solution.
-
-
Effect on Blue Litmus Paper:
-
Litmus paper is an indicator used to test the acidity or alkalinity of a solution. Blue litmus paper turns red in the presence of an acid.
-
When the carbonic acid forms and dissociates, the increase in hydrogen ions (H^+) causes the blue litmus paper to change color.
-
As a result, the moist blue litmus paper will turn red in the presence of CO₂ gas due to the acidic nature of the resulting solution:
\text{Blue Litmus Paper} + H^+ \rightarrow \text{Red Litmus Paper}
-
Final Answer:
When a moist blue litmus paper is brought near CO₂ gas, it will turn red because the carbon dioxide reacts with water to form carbonic acid, increasing acidity and causing the color change to red.