Horrock’s apparatus

Correct answer : d

Horrocks Apparatus : 

• It is used to find out the dose of bleaching powder required for disinfection of water. 

• It consists of : 

• One black cup (200 ml ) with a marking inside. 

• Six white cups (200 ml ). 

• Seven glass stirring rods. 

• One pipette. 

• Two droppers. 

• Starch-iodide indicator solution. 

• Bleaching powder.

 • Two metal spoons which can hold 2 gms of bleaching powder in each. 

• Plastic or wooden box container for all these items.