Download App

Electrochemistry — Chemistry STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 ScienceChemistryElectrochemistry3 Marks
Question
Classification of solid based on conductivity
✓

Answer

→ Materials are classified into conductors, insulators and semiconductors depending on the magnitude of their conductivity.
→ Metals and their alloys have very high conductivity and are known as conductors.
→ Certain non-metals like carbon-black, graphite and some organic polymers* are also possess electronically conductivity.
→ Substances like glass, ceramics, etc., having very low conductivity are known as insulators.
→ Substance like silicon, doped silicon and gallium arsenide having conductivity between conductors and insulators are called semiconductors and are important electronic materials.
→ Certain material called superconductors exhibit zero resistivity or infinite conductivity.
→ Earlier, only metals and their alloys at very low temperatures (0 to 15 K) were known to behave as superconductors, but now days a number of ceramic materials and mixed oxides are also known to show superconductivity at temperatures as high as 150 K.
→ The values of Conductivity of some Selected Materials at 298.15 K are given below.
MaterialConductivity/S$m ^{-1}$MaterialConductivity/S$m ^{-1}$
Conductors Aqueous Solution
Sodium$2.1 \times 10^3$Pure water$3.5 \times 10^{-5}$
Copper$5.9 \times 10^3$0.1 M HCl3.91
Silver$6.2 \times 10^3$0.01 M KCI0.14
Gold$4.5 \times 10^3$0.01M NaCl0.12
Iron$1.0 \times 10^3$0.1 M HAc0.047
Graphite$1.2 \times 10$0.01M HAc0.016
Insulators Semiconductors
Glass$1.0 \times 10^{-16}$CuO$1 \times 10^{-7}$
Teflon$1.0 \times 10^{-18}$Si$1.5 \times 10^{-2}$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "3 Marks Question" from Electrochemistry→Electrochemistry — all question types→Chemistry STD 12 Science question papers→Gujarat Board STD 12 Science question papers→Gujarat Board question paper generator→

Similar questions

How would you account for the following? 
  1. Many of the transition elements are known to form interstitial compounds.
  2. The metallic radii of the third (5d) series of transition metals are virtually the same as those of the corresponding group members of the second (4d) series.
  3. Lanthanoids form primarily +3 ions, while the actinoids usually have higher oxidation states in their compounds, +4 or even +6 being typical.
→
Give reasons:
  1. C–Cl bond length in chlorobenzene is shorter than C–Cl bond length in CH3–Cl.
  2. The dipole moment of chlorobenzene is lower than that of cyclohexyl chloride.
  3. SN1 reactions are accompanied by racemization in optically active alkyl halides.
→
  1. The cell in which the following reaction occurs:

2 Fe3+ (aq) + 2 I- (aq) $\longrightarrow$ 2 Fe2+ (aq) + I2 (s)

has $\text{E}^0_{\text{cell}}$ = 0·236 V at 298 K. Calculate the standard Gibbs energy of the cell reaction. (Given : 1 F = 96,500 C mol-1)

  1. How many electrons flow through a metallic wire if a current of 0·5 A is passed for 2 hours? (Given : 1 F = 96,500 C mol-1)
→
What is azeotropes? Explain it's Types.
→
Why haloalkanes undergo nucleophilic substitution reaction whereas haloarenes undergo electrophilic substitution reaction, why?
→
Write the IUPAC name of Fe4 [Fe(CN)6]3.
→
Draw the structures of the following derivatives:
  1. The 2,4-Dinitrophenylhydrazone of benzaldehyde.
  2. Acetaldehyde dimethyl acetal.
  3. Cyclopropanone oxime.
→
Explain nucleophilic addition reaction of aldehydes and ketones with hydrogen cyanide (HCN).
→
  1. Describe the following giving suitable examples:
  1. Cannizzaro reaction.
  2. Aldol condensation.
  1. ​​​​​​​Give a chemical test to distinguish between ethanal and propanal.
→
Explain solubility of gas in a liquid solvent.
→