Advertisements
Advertisements
Question
Alkali metals react with water vigorously to form hydroxides and dihydrogen. Which of the following alkali metals reacts with water least vigorously?
Options
Li
Na
K
Cs
Advertisements
Solution
Li
Explanation:
Both melting point and heat of reaction of alkali metals with water decrease down the group from Li to Cs. Although the heat of reaction of Li is the highest, but due to its high melting point, even this heat is not sufficient to melt the metal, which exposes greater surface to water for reaction. As a result, Li has the least reactivity but the reactivity increases as the melting point of alkali metals decreases down the group from Li to Cs.
APPEARS IN
RELATED QUESTIONS
Why are alkali metals not found in nature?
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.
Which of the following statements is incorrect?
Metals form basic hydroxides. Which of the following metal hydroxide is the least basic?
By adding gypsum to cement
Which of the following elements does not form hydride by direct heating with dihydrogen?
Which of the following compounds are readily soluble in water?
(i) BeSO4
(ii) MgSO4
(iii) BaSO4
(iv) SrSO4
Choose the correct statements from the following.
(i) Beryllium is not readily attacked by acids because of the presence of an oxide film on the surface of the metal.
(ii) Beryllium sulphate is readily soluble in water as the greater hydration enthalpy of Be2+ overcomes the lattice enthalpy factor.
(iii) Beryllium exhibits coordination number more than four.
(iv) Beryllium oxide is purely acidic in nature.
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:
The metal mainly used in devising photoelectric cells is ______.
KO2 (potassium super oxide) is used in oxygen cylinders in space and submarines because it ______.
Alkali metals are powerful reducing agents because ______.
Which element from following is used as moderator in nuclear reactor?
