Advertisements
Advertisements
प्रश्न
Why are lithium salts commonly hydrated and those of the other alkali metal ions usually anhydrous?
Advertisements
उत्तर
Lithium is the smallest in size among the alkali metals. Hence, Li+ ion can polarize water molecules more easily than other alkali metals. As a result, water molecules get attached to lithium salts as water of crystallization. Hence, lithium salts such as trihydrated lithium chloride (LiCl.3H2O) are commonly hydrated. As the size of the ions increases, their polarizing power decreases. Hence, other alkali metal ions usually form anhydrous salts.
संबंधित प्रश्न
What are the common chemical features of alkali metals?
Explain why alkali and alkaline earth metals cannot be obtained by chemical reduction methods?
Why are potassium and cesium, rather than lithium used in photoelectric cells?
When an alkali metal dissolves in liquid ammonia the solution can acquire different colours. Explain the reasons for this type of colour change.
Write a balanced equation for the reaction between KO2 and water.
Which of the alkali metal is having least melting point?
For alkali metals, which one of the following trends is incorrect?
Which of the following statements is incorrect?
The solubility of metal halides depends on their nature, lattice enthalpy and hydration enthalpy of the individual ions. Amongst fluorides of alkali metals, the lowest solubility of LiF in water is due to ______.
By adding gypsum to cement
Metallic elements are described by their standard electrode potential, fusion enthalpy, atomic size, etc. The alkali metals are characterised by which of the following properties?
(i) High boiling point.
(ii) High negative standard electrode potential.
(iii) High density.
(iv) Large atomic size.
When heated in air, the alkali metals form various oxides. Mention the oxides formed by Li, Na and K.
When a metal of group 1 was dissolved in liquid ammonia, the following observations were obtained:
(i) Blue solution was obtained initially.
(ii) On concentrating the solution, blue colour changed to bronze colour.
How do you account for the blue colour of the solution? Give the name of the product formed on keeping the solution for some time.
The stability of peroxide and superoxide of alkali metals increase as we go down the group. Explain giving reason.
The valence shell electronic configuration of alkali metals is ______.
The ease of absorption of the hydrated alkali metals ions in an ion-exchange resin follows the order:
Match List-I with List-II.
| List-I | List-II |
| (Metal) | (Application) |
| (a) Cs | (I) High temperature thermometer |
| (b) Ga | (II) Water repellent sprays |
| (c) B | (III) Photoelectric cells |
| (d) Si | (IV) Bullet proof vest |
Choose the most appropriate answer from the options given below:
The metal mainly used in devising photoelectric cells is ______.
The correct order of hydration enthapies of alkali metal ions is ______.
