Page 231 - Chemistry ICSE Class IX
P. 231
Chemistry Practicals 219
EXPERIMENT 4.1
Objective
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'ZRGTKOGPV Observations Inference
Salt 1: Make the paste of the given
salt 1 with conc. HCl. Perform the
ame test and observe colour of the
ame
+
with naked eyes. Golden yellow Sodium ion (Na ).
through blue glass. Invisible 6JG IKXGP UCNV KU C EQORQWPF
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Salt 2: Make the paste of the given
salt 2 with conc. HCl. Perform the
ame test and observe colour of the
ame
+
with naked eyes. Violet (purple) Potassium ion (K )
through blue glass. Pink 6JG IKXGP UCNV KU C EQORQWPF
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Salt 3: Make the paste of the given
salt 3 with conc. HCl. Perform the
ame test and observe colour of the
ame
2+
with naked eyes. Brick-red Calcium ion (Ca )
through blue glass. Light yellow 6JG IKXGP UCNV KU C EQORQWPF
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VIVA VOCE
1. Why is platinum wire/loop used in flame test?
Ans. Platinum has high melting point and does not get oxidised during heating. It also does not impart any colour of its own
to the flame.
2. Which part of the flame is called oxidising flame?
Ans. The outer nonluminous part of the flame is called oxidising flame.
3. Why is conc. hydrochloric acid used for making paste of the salt to be tested?
Ans. This is to convert salts, such as oxides and carbonates, to chlorides. Chlorides being more volatile give better results.
4. When a glass rod is introduced in a nonluminous flame, it imparts golden-yellow colour to the flame. What do you
conclude from it?
Ans. It indicates that glass contains sodium ions.
