When carbondioxide is bubbled into limewater a white precipitate is formed. If the passage of the gas is continued, the precipitate disappears. The reason for this is

Eby2021

2 years ago

The correct answer is:

C. calcium carbonate is formed which on reaction with further carbon dioxide forms soluble calcium hydrogen carbonate

Initially, when carbon dioxide is bubbled into limewater (which contains calcium hydroxide), it forms insoluble calcium carbonate precipitate. However, as more carbon dioxide is introduced, it reacts with the calcium carbonate to form soluble calcium hydrogen carbonate, which dissolves in the solution, hence the disappearance of the precipitate.

DrSponsor

3 months ago

̲𝗦​̲𝘁​̲𝗲​̲𝗽​̲ ​̲𝟭 — CO₂ bubbled into limewater

Limewater = calcium hydroxide solution (Ca(OH)₂).

When carbon dioxide is first passed through it:

𝗖𝗢₂ + 𝗖𝗮(𝗢𝗛)₂ → 𝗖𝗮𝗖𝗢₃ + 𝗛₂𝗢

Here:

CaCO₃ (calcium carbonate) forms

𝗖𝗮𝗹𝗰𝗶𝘂𝗺 𝗰𝗮𝗿𝗯𝗼𝗻𝗮𝘁𝗲 𝗶𝘀 𝗶𝗻𝘀𝗼𝗹𝘂𝗯𝗹𝗲

So it appears as a 𝘄𝗵𝗶𝘁𝗲 𝗽𝗿𝗲𝗰𝗶𝗽𝗶𝘁𝗮𝘁𝗲

That’s why 𝗹𝗶𝗺𝗲𝘄𝗮𝘁𝗲𝗿 𝘁𝘂𝗿𝗻𝘀 𝗺𝗶𝗹𝗸𝘆.

​̲𝗦​̲𝘁​̲𝗲​̲𝗽​̲ ​̲𝟮​̲ — Passing more CO₂

If you continue bubbling CO₂, another reaction occurs.

The precipitate calcium carbonate reacts with more CO₂ and water:

𝗖𝗮𝗖𝗢₃ + 𝗖𝗢₂ + 𝗛₂𝗢 → 𝗖𝗮(𝗛𝗖𝗢₃)₂

This is called calcium hydrogen carbonate.

Important point:

𝗖𝗮𝗹𝗰𝗶𝘂𝗺 𝗵𝘆𝗱𝗿𝗼𝗴𝗲𝗻 𝗰𝗮𝗿𝗯𝗼𝗻𝗮𝘁𝗲 𝗶𝘀 𝘀𝗼𝗹𝘂𝗯𝗹𝗲 𝗶𝗻 𝘄𝗮𝘁𝗲𝗿.

𝗦𝗼 𝘁𝗵𝗲 𝘄𝗵𝗶𝘁𝗲 𝗽𝗿𝗲𝗰𝗶𝗽𝗶𝘁𝗮𝘁𝗲 𝗱𝗶𝘀𝘀𝗼𝗹𝘃𝗲𝘀, 𝗮𝗻𝗱 𝘁𝗵𝗲 𝘀𝗼𝗹𝘂𝘁𝗶𝗼𝗻 𝗯𝗲𝗰𝗼𝗺𝗲𝘀 𝗰𝗹𝗲𝗮𝗿 𝗮𝗴𝗮𝗶𝗻.


Correct Answer is C. calcium carbonate is formed which on reaction with further carbon dioxide forms soluble calcium hydrogen carbonate
Correct explanation.