Method of Purification Notes Questions with Answers PDF Download - 7

Alternative techniques to crystallization involve

1. decanting only
2. centrifuging
3. filtration
4. decanting and centrifuging

If molten Lead Bromide (PbBr₂) is electrolyzed,

1. at anode, brown fumes of bromide gas are given off
2. at anode, molten lead can be seen
3. at cathode, brown fumes can be seen
4. at cathode, lead bromide can be seen

In an acidified solution of Potassium Dichromate(VI) (K₂Cr₂O₇), Dichromate ion (Cr₂O₇^-2) becomes reduced to

1. Chromate (V) ions
2. Chromium (III) ions
3. Chromium (II) ions
4. Chromium (VI) ions

Which one of them is correct about electronic thermometers?

1. there is mercury in glass thermometer
2. there is alcohol in glass thermometer
3. they are used to reduce the risk of mercury poisoning if broken
4. none of above

In the periodic table, the period number indicates the number of

1. neutrons
2. protons
3. electrons
4. photons