The table shows the concentration of some ions present in seawater. name of ion formula of ion concentration of ion in g / dm 3 bromide Br - 0 . 07 calcium Ca 2 + 0 . 04 chloride Cl - 19 . 1 magnesium Mg 2 + 1 . 2 potassium K + 0 . 3 sodium Na + 10 . 6 SO 4 2 - 0 . 8 Name the four ions in the table which move to the cathode when seawater is electrolysed.

Seawater consists of salts of various elements. On electrolysis, these salts get separated in the form of their ions like sodium, chloride, potassium, etc. During electrolysis, the ions are separated and move to the electrodes of opposite charges. Thus, ions with negative charge move towards the anode, while ions with positive charge move towards the cathode. Of the given ions, sodium ions, potassium ions, magnesium ions and calcium ions move towards the cathode. They undergo reduction to form corresponding atoms.

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Upper Secondary: IGCSE

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A student electrolysed molten zinc chloride. State the name of the product formed at the anode.

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Important Questions on Cambridge IGCSE Exam Questions from Paper 2

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Upper Secondary: IGCSE

IMPORTANT

Complete Chemistry for Cambridge IGCSE® Second Edition>Chapter 20 - Cambridge IGCSE Exam Questions from Paper 2>CAMBRIDGE IGCSE EXAM QUESTIONS from Paper 2>Q 5

A student electrolysed molten zinc chloride. State the name of the product formed at the cathode.

EASY

Upper Secondary: IGCSE

IMPORTANT

Complete Chemistry for Cambridge IGCSE® Second Edition>Chapter 20 - Cambridge IGCSE Exam Questions from Paper 2>CAMBRIDGE IGCSE EXAM QUESTIONS from Paper 2>Q 6

Sodium has only one stable isotope whereas potassium has several isotopes. What do you understand by the term isotopes?

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Upper Secondary: IGCSE

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Complete Chemistry for Cambridge IGCSE® Second Edition>Chapter 20 - Cambridge IGCSE Exam Questions from Paper 2>CAMBRIDGE IGCSE EXAM QUESTIONS from Paper 2>Q 6

Sodium has only one stable isotope whereas potassium has several isotopes. How many protons does sodium have in its nucleus? Use the Periodic Table to help you.

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Upper Secondary: IGCSE

IMPORTANT

Complete Chemistry for Cambridge IGCSE® Second Edition>Chapter 20 - Cambridge IGCSE Exam Questions from Paper 2>CAMBRIDGE IGCSE EXAM QUESTIONS from Paper 2>Q 7

The table shows the concentration of some ions present in seawater.

name of ion	formula of ion	concentration of ion in $g / {dm}^{3}$
bromide	${Br}^{-}$	$0.07$
calcium	${Ca}^{2 +}$	$0.04$
chloride	${Cl}^{-}$	$19.1$
magnesium	${Mg}^{2 +}$	$1.2$
potassium	$K^{+}$	$0.3$
sodium	${Na}^{+}$	$10.6$
	${SO}_{4}^{2 -}$	$0.8$

Which negative ion has the highest concentration in seawater?

EASY

Upper Secondary: IGCSE

IMPORTANT

Complete Chemistry for Cambridge IGCSE® Second Edition>Chapter 20 - Cambridge IGCSE Exam Questions from Paper 2>CAMBRIDGE IGCSE EXAM QUESTIONS from Paper 2>Q 7

The table shows the concentration of some ions present in seawater.

name of ion	formula of ion	concentration of ion in $g / {dm}^{3}$
bromide	${Br}^{-}$	$0.07$
calcium	${Ca}^{2 +}$	$0.04$
chloride	${Cl}^{-}$	$19.1$
magnesium	${Mg}^{2 +}$	$1.2$
potassium	$K^{+}$	$0.3$
sodium	${Na}^{+}$	$10.6$
	${SO}_{4}^{2 -}$	$0.8$

When seawater is evaporated a number of different compounds are formed. State the name of the compound present in the greatest quantity.

EASY

Upper Secondary: IGCSE

IMPORTANT

Complete Chemistry for Cambridge IGCSE® Second Edition>Chapter 20 - Cambridge IGCSE Exam Questions from Paper 2>CAMBRIDGE IGCSE EXAM QUESTIONS from Paper 2>Q 7

The table shows the concentration of some ions present in seawater.

name of ion	formula of ion	concentration of ion in $g / {dm}^{3}$
bromide	${Br}^{-}$	$0.07$
calcium	${Ca}^{2 +}$	$0.04$
chloride	${Cl}^{-}$	$19.1$
magnesium	${Mg}^{2 +}$	$1.2$
potassium	$K^{+}$	$0.3$
sodium	${Na}^{+}$	$10.6$
	${SO}_{4}^{2 -}$	$0.8$

Name the four ions in the table which move to the cathode when seawater is electrolysed.

EASY

Upper Secondary: IGCSE

IMPORTANT

Complete Chemistry for Cambridge IGCSE® Second Edition>Chapter 20 - Cambridge IGCSE Exam Questions from Paper 2>CAMBRIDGE IGCSE EXAM QUESTIONS from Paper 2>Q 7

When concentrated seawater is electrolysed, chlorine is formed at one of the electrodes. Draw the electronic structure of a chlorine molecule. Show only the outer electrons.

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Upper Secondary: IGCSE

IMPORTANT

Complete Chemistry for Cambridge IGCSE® Second Edition>Chapter 20 - Cambridge IGCSE Exam Questions from Paper 2>CAMBRIDGE IGCSE EXAM QUESTIONS from Paper 2>Q 7

Drinking water can be obtained by purifying seawater. Explain why distillation rather than filtration is used to purify seawater for drinking.

A student electrolysed molten zinc chloride. State the name of the product formed at the anode.

Important Questions on Cambridge IGCSE Exam Questions from Paper 2

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