S-Block Elements Test - 10

The apparatus shown is divided into two types of cells separated by slate walls:
(i) Shown on the right and left of the diagram, uses an electrolyte of sodium chloride solution, a graphite anode (A), and a mercury cathode (M).
(ii) Shown in the centre of the diagram, uses an electrolyte of sodium hydroxide solution, a mercury anode (M), and an iron cathode (D).

The mercury electrode is common between the two cells. This is achieved by having the walls separating the cells dip below the level of the electrolytes but still allow the mercury to flow beneath them.

Heating limestone at a temperature of 1070K we get quick lime i.e CaO.

CaCO₃ ⇌ CaO (s) + CO₂ (s)

On passing CO₂ gas, Ca(OH)₂ becomes CaCO₃ (milky white ppt.) which proves the presence of CO₂.

If CO₂ is passed through slaked lime(calcium hydroxide Ca(OH)₂), it gives out calcium carbonate (CaCO₃) also called marble/limestone.

Reaction: CO₂ + Ca(OH)₂→ CaCO₃+ H₂O

Teeth are composed of calcium, phosphorus, and other minerals. But bones are still not as strong as teeth. The hardest part of the human body, teeth mostly consist of a calcified tissue called dentin. The tooth's dentine tissue is covered in enamel, that hard, shiny layer that you brush.

In castner-kellner method NaOH is prepared by the electrolysis of aqueous solution of NaCl(Brine).

Slaked lime (milk of lime) reacts with chlorine gas to produce the bleaching agent calcium hypochlorite – a common form of 'swimming pool' chlorine.

Sodium carbonate, Na₂CO₃, (washing soda) is the water-soluble sodium salt of carbonic acid, well-known domestically for its everyday use as a water softener.
Pure sodium carbonate is a white, odorless powder that is hygroscopic (absorbs moisture from the air). It has a strongly alkaline taste and forms a moderately basic solution in water.

Crystallization: A chemical solid-liquid separation technique in which mass transfer of a solute from the liquid solution to a pure solid crystalline phase occurs.

Calcium hypochlorite is an inorganic compound with formula Ca(OCl)₂. It is the main active ingredient of commercial products called bleaching powder