Differentiate between an element and a compound. Categorize the following substances into elements and compounds: Sodium chloride,Iodine,Water,$24$ carat gold,Oxygen gas,Carbon.

$(a)$ Differentiate between a mixture and a compound.
$(b)$ You are provided with a mixture containing sand,iron filings,naphthalene,and sodium chloride. Describe the procedures you would use to separate these constituents from the mixture.

Identify the dispersed phase and dispersing medium in the following colloids:
$(a)$ Fog
$(b)$ Cheese
$(c)$ Coloured gemstone

State the separation technique you would apply for the separation of the following:
$(a)$ Sodium chloride from its solution in water
$(b)$ Tea leaves from tea
$(c)$ Iron pins from sand
$(d)$ Different pigments from an extract of leaves
$(e)$ Butter from curd
$(f)$ Fine mud particles suspended in water.

Suggest separation technique$(s)$ one would need to employ to separate the following mixtures:
$(a)$ Mercury and water
$(b)$ Potassium chloride and ammonium chloride
$(c)$ Common salt,water and sand
$(d)$ Kerosene oil,water and salt

Which of the following are not compounds?
$(a)$ Chlorine gas
$(b)$ Potassium chloride
$(c)$ Iron
$(d)$ Iron sulphide
$(e)$ Aluminium
$(f)$ Iodine
$(g)$ Carbon
$(h)$ Carbon monoxide
$(i)$ Sulphur powder