Why are potassium and caesium, rather than lithium used in photo

Previous Year Papers

Download Solved Question Papers Free for Offline Practice and view Solutions Online.

Test Series

Take Zigya Full and Sectional Test Series. Time it out for real assessment and get your results instantly.

Test Yourself

Practice and master your preparation for a specific topic or chapter. Check you scores at the end of the test.
Advertisement

 Multiple Choice QuestionsShort Answer Type

91.

The ionic radii of alkali metal ions in aqueous solution follows the order Li+ > Na+> K+ > Rb+ > CsJustify the above order.

703 Views

 Multiple Choice QuestionsLong Answer Type

92.

Discuss the general trends in ionisation enthalpy and electropositive character of alkali metals.

213 Views

 Multiple Choice QuestionsShort Answer Type

93.

Why do alkali metals impart characteristic colours to the flame?

1783 Views

94.

Why do alkali metals from unipositive ions?

371 Views

Advertisement
95.

Lithium ion has the lowest and caesium ion has the highest mobility in an electric field. Explain. 

149 Views

96.

When an alkali metal dissolves in liquid ammonia the solution can acquire different colours. Explain the reactions for this type of colour change.
Or
Explain why alkali metals dissolve in liquid ammonia to form deep blue solution.

1523 Views

97.

Explain why alkali metals are electrically conducting and form soluble salts ?

221 Views

98.

How will you explain that alkali metals are chemically highly receive?

155 Views

Advertisement
Advertisement

99.

Why are potassium and caesium, rather than lithium used in photoelectric cells?


This is because potassium and caesium have much lower ionisation enthalpy than that of lithium. As a result, these two metals when subjected to light, emit electrons but lihtium does not. Hence potassium and caesium, rather than lithium is used in photoelectric cells.
153 Views

Advertisement
100.

How will you explain that alkali metals are strong reducing agents?

354 Views

Advertisement