Question

in liquid-liquid electrode the two liquids are separated by
cause the exchange of ions ( 1 marks)
Porous membrane
Liquid membrane
Glass membrane
Crystal membrane​

Answer 1

liquid membrane

It consists of a liquid phase (e.g. a thin oil film) existing either in supported or unsupported form that serves as a membrane barrier between two phases of aqueous solutions or gas mixtures.

Answer 2

In a liquid-liquid electrode, the two liquids are separated by a liquid membrane which causes the exchange of ions

Electrochemistry:

• Electrochemistry is the study of the use of electrical energy to produce electricity and bring about non-spontaneous chemical changes from the energy released during spontaneous chemical reactions.
• There are two types of electrochemical cells - galvanic or voltaic and electrolytic.
• Galvanic cells derive their energy from spontaneous redox reactions, whereas electrolytic cells involve non-spontaneous reactions and thus require an external electron source such as a DC battery or an AC power source.

Liquid membrane electrodes:

• An ion-exchanger or ionophore (neutral macrocyclic ion carrier) is dissolved in a viscous organic liquid membrane.
• Without an exchanger or ionophore, the ion of interest is unable to penetrate the membrane.
• One of the best-known liquid membrane electrodes has been used for calcium determination.
• Initially, the researchers attempted to use glass membrane electrodes (which were successful for monovalent cations such as $H^{+}$ and $Na^{+}$) to detect divalent cations such as Ca.
• When this was determined to be infeasible, liquid membranes were developed.
• This electrode works by the ion-exchange process.
• The cation-exchanger is an aliphatic diester of phosphoric acid, $(RO)_{2} PO_{2} ^{-}$, where each R group is an aliphatic hydrocarbon chain containing 8 and 16 carbons.
• The phosphate group can be protonated but has a strong affinity for $Ca^{2+}$.
• The cation exchanger is dissolved in an organic solvent and placed in a porous compartment between the analysis solution and the internal reference calcium chloride solution.

Liquid-ion-exchanger electrodes use a liquid ion exchanger encased in an inert, porous hydrophobic membrane.

The electrodes are selective because ion exchangers selectively exchange a single analyte ion.