When chlorine is passed over slaked lime the main reaction products are:

A. $Ca(ClO_2)_2$
B. $CaCl_2$
C. $Ca(OCl)_2$
D. $Ca(OCl_2)$

Choose the correct answer from the options given below:

B and C only

The correct answer is Option (2) → B and C only.

When chlorine gas \((Cl_2)\) is passed over slaked lime \((Ca(OH)_2)\), a well-known chemical reaction occurs that produces calcium chloride \((CaCl_2)\) and calcium hypochlorite \((Ca(OCl)_2)\). This reaction is important in the production of bleaching powder, which is widely used as a disinfectant and bleaching agent.

Reaction Overview: The reaction between chlorine and slaked lime can be represented by the following balanced equation:

\(2Cl_2 + 2Ca(OH)_2 \longrightarrow Ca(OCl)_2 + CaCl_2 + 2H_2O\)

Detailed Breakdown of the Reaction:

Slaked Lime: Slaked lime, chemically known as calcium hydroxide \((Ca(OH)_2)\), is a basic compound and reacts with chlorine.

Chlorine: Chlorine gas \((Cl_2)\) is a diatomic molecule that is highly reactive, especially with basic compounds like calcium hydroxide.

Reaction Mechanism: When chlorine gas reacts with calcium hydroxide, two different products are formed:

Calcium hypochlorite \((Ca(OCl)_2)\): This is the main active ingredient in bleaching powder and is used for disinfection and bleaching purposes.

Calcium chloride \((CaCl_2): This is a by-product of the reaction and is commonly used in road de-icing and as a drying agent.

The reaction can be thought of as chlorine disproportionation, where chlorine simultaneously gets oxidized and reduced: One chlorine molecule is reduced from 0 to -1 oxidation state (forming \(Cl^-\) in \(CaCl_2\)).

Another chlorine molecule is oxidized from 0 to +1 oxidation state (forming \(OCl^-\) in \(Ca(OCl)_2\)).

Water Formation:

Water \((H_2O)\) is also produced in the reaction as a result of the interaction between chlorine gas and the hydroxide ions from slaked lime.

Products of the Reaction:

Calcium hypochlorite \((Ca(OCl)_2)\):

This is the hypochlorite form of calcium, where the chlorine is in the +1 oxidation state. 

It is a powerful oxidizing agent and is responsible for the bleaching and disinfecting properties of bleaching powder.

Calcium chloride \((CaCl_2)\):

This compound is formed by the complete reduction of chlorine to the chloride ion \((Cl^-)\) in the -1 oxidation state. Calcium chloride is highly soluble in water and serves as a by-product of this reaction.

Summary:

When chlorine reacts with slaked lime, it produces two main products: calcium hypochlorite \((Ca(OCl)_2)\), used in bleaching powder, and calcium chloride \((CaCl_2)\) as a by-product. The equation for this reaction is:

\(2Cl_2 + 2Ca(OH)_2 \longrightarrow Ca(OCl)_2 + CaCl_2 + 2H_2O\)