IGCSE Chemistry: Specimen Questions with Answers 35 - 37 of 240

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Question 35

Write in Short

Short Answer▾

The diagram shows an electrolysis circuit.

At which electrode is hydrogen formed?

Electrolysis Circuit

Explanation

Correct Answer is A because only aqueous sodium chloride solution takes place in electrolysis and produce ions. The water reaction would have produced H + ions though, making the water acidic at the anode. The indicator didn՚t change to the acid color, it just turned the color of bleach. When you bubble Chlorine through water, you get the Hypochlorite ion through. At the cathode where the reduction of water occurred (favored over the reduction of Na + ) as shown in figure.

Question 36

Question

MCQ▾

What is the chemical formula of Ozone?

Choices

Choice (4)

a.

b.

c.

d.

O

Answer

a.

Explanation

is the chemical formula of Ozone.

Question 37

Question

MCQ▾

The elements of which group are known as metalloids?

Choices

Choice (4)

a.

b.

c.

d.

Answer

b.

Explanation

  • The elements of group have valence electrons. So it is not at all easy for the elements of the group to give electrons in order to achieve octet configuration. At the same time, it is also difficult for the group elements to accommodate four extra electrons in order to achieve octet configuration. Hence they mostly share their valence electrons but do not transfer.
  • Therefore they are known as metalloids as they neither give electrons like metals not accept electrons like nonmetals.

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