Class 11 Chemistry - Chapter The s Block Elements NCERT Solutions | What happens when (i) sodium metal is
What happens when
(i) sodium metal is dropped in water ?
(ii) sodium metal is heated in free supply of air ?
(iii) sodium peroxide dissolves in water ?
(i) When Na metal is dropped in water, it reacts violently to form sodium hydroxide and hydrogen gas. The chemical equation involved in the reaction is:
2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g)
(ii) On being heated in air, sodium reacts vigorously with oxygen to form sodium peroxide. The chemical equation involved in the reaction is:
2Na(s) + O2(s) → Na2O2(s)
(iii) When sodium peroxide is dissolved in water, it is readily hydrolysed to form sodium hydroxide and water. The chemical equation involved in the reaction is:
Na2O2(s) + 2H2O(l) → 2NaOH(aq) + H2O2(aq)
More Questions From Class 11 Chemistry - Chapter The s Block Elements
- Q:-
Compare the alkali metals and alkaline earth metals with respect to
(i) ionization enthalpy
(ii) basicity of oxides and
(iii) solubility of hydroxides.
- Q:-
Compare the solubility and thermal stability of the following compounds of the alkali metals with those of the alkaline earth metals.
(a) Nitrates (b) Carbonates (c) Sulphates.
- Q:-
Discuss the various reactions that occur in the Solvay process.
- Q:-
Comment on each of the following observations:
(a) The mobilities of the alkali metal ions in aqueous solution are Li+ < Na+ < K+ < Rb+ < Cs+
(b) Lithium is the only alkali metal to form a nitride directly.
(c) E° for M2+(aq) (where M = Ca, Sr or Ba) is nearly constant.
- Q:-
Why are lithium salts commonly hydrated and those of the other alkali metal ions usually anhydrous?
- Q:-
State as to why
(a) a solution of Na2CO3 is alkaline ?
(b) alkali metals are prepared by electrolysis of their fused chlorides ?
(c) sodium is found to be more useful than potassium ?
- Q:-
When an alkali metal dissolves in liquid ammonia the solution can acquire different colours. Explain the reasons for this type of colour change.
- Q:-
In what ways lithium shows similarities to magnesium in its chemical behaviour?
- Q:-
Why is Li2CO3 decomposed at a lower temperature whereas Na2CO3 at higher temperature?
- Q:-
Find the oxidation state of sodium in Na2O2.
Popular Questions of Class 11 Chemistry
- Q:-
How do you account for the formation of ethane during chlorination of methane?
- Q:-
What are hybridisation states of each carbon atom in the following compounds ?
(i) CH2=C=O,
(ii) CH3CH=CH2,
(iii) (CH3)2CO,
(iv) CH2=CHCN,
(v) C6H6
- Q:-
What will be the minimum pressure required to compress 500 dm3 of air at 1 bar to 200 dm3 at 30°C?
- Q:-
Calculate the molecular mass of the following:
(i) H2O
(ii) CO2
(iii) CH4 - Q:-
Assign oxidation number to the underlined elements in each of the following species:
(a) NaH2PO4
(b) NaHSO4
(c) H4P2O7
(d) K2MnO4
(e) CaO2
(f) NaBH4
(g) H2S2O7
(h) KAl(SO4)2.12 H2O
- Q:-
What is the basic theme of organisation in the periodic table?
- Q:-
Explain the formation of a chemical bond.
- Q:-
Choose the correct answer. A thermodynamic state function is a quantity
(i) used to determine heat changes
(ii) whose value is independent of path
(iii) used to determine pressure volume work
(iv) whose value depends on temperature only. - Q:-
A liquid is in equilibrium with its vapour in a sealed container at a fixed temperature. The volume of the container is suddenly increased.
a) What is the initial effect of the change on vapour pressure?
b) How do rates of evaporation and condensation change initially?
c) What happens when equilibrium is restored finally and what will be the final vapour pressure? - Q:-
Justify the position of hydrogen in the periodic table on the basis of its electronic configuration.
Recently Viewed Questions of Class 11 Chemistry
- Q:-
The pH of a sample of vinegar is 3.76. Calculate the concentration of hydrogen ion in it.
- Q:-
Calculate the volume occupied by 8.8 g of CO2 at 31.1°C and 1 bar pressure.
R = 0.083 bar L K–1 mol–1.
- Q:-
Which of the followings are Lewis acids? H2O, BF3, H+ and NH+4
- Q:-
Describe the hybridisation in case of PCl5. Why are the axial bonds longer as compared to equatorial bonds?
- Q:-
Boric acid is polymeric due to
(a) its acidic nature (b) the presence of hydrogen bonds (c) its monobasic nature (d) its geometry
- Q:-
The drain cleaner, Drainex contains small bits of aluminum which react with caustic soda to produce dihydrogen. What volume of dihydrogen at 20 °C and one bar will be released when 0.15g of aluminum reacts?
- Q:-
A sample of pure PCl5 was introduced into an evacuated vessel at 473 K. After equilibrium was attained, concentration of PCl5 was found to be 0.5 × 10–1 mol L–1. If value of Kc is 8.3 × 10–3, what are the concentrations of PCl3 and Cl2 at equilibrium?
PCl5 (g) ↔ PCl3 (g) + Cl2(g)
- Q:-
Describe the change in hybridisation (if any) of the Al atom in the following reaction.
- Q:-
Identify the reagents shown in bold in the following equations as nucleophiles or electrophiles:
(a) CH3COOH + HO- → CH3COO- + H2O
(b) CH3COCH3 + C-N → (CH3)2 C (CN) (OH)
(c) C6H5 + CH3C+O → C6H5COCH3
- Q:-
What is smog? How is classical smog different from photochemical smog?
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