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New answer posted
a year ago
Contributor-Level 10
This is a Matching Type Questions as classified in NCERT Exemplar
56. (i) → (e); (ii) → (d); (iii) → (a) : (iv) → (b); (v) → (c)
New answer posted
a year agoContributor-Level 10
This is a Multiple Choice Questions as classified in NCERT Exemplar
55. Options (i) and (ii) are correct since hyperconjugation involves the delocalization of electrons of C—H bond of an alkyl group directly attached to an atom of unsaturated system or to an atom with an unshared p-orbital. The electrons of C—H bond of the alkyl group enter into partial conjugation with the attached unsaturated system or with the unshared p-orbital. This is a permanent effect. Hyperconjugation can be shown as-
New answer posted
a year agoContributor-Level 10
This is a long answer type question as classified in NCERT Exemplar
The element imparts yellow colour to the flame in flame test which means the element of group 1 is sodium. Sodium is used in the transmission of nerve signals and transport of sugars and amino acids into cells. Reactions are shown below.
2Na+O2→Na2O2
4Na+O2→2Na2O
2Na2O+O2→2Na2O2
New answer posted
a year agoContributor-Level 10
This is a long answer type question as classified in NCERT Exemplar
In group 2, only beryllium is amphoteric in nature which means it reacts with both acids and bases. Also, beryllium only forms covalent oxide due to the covalent nature. So, the element is beryllium.
It reacts with acid to form beryllium chloride and it reacts with base to form beryllate ion which is soluble in sodium hydroxide. The reaction is shown below.
Be (OH)2+2OH− → [Be (OH)4]2−
Be (OH)2+2HCl →BeCl2+2H2O
New answer posted
a year agoContributor-Level 10
This is a long answer type question as classified in NCERT Exemplar
Beryllium being least reactive does not form hydride by direct heating with dihydrogen. It is prepared by reacting it with lithium aluminum hydride. The reactions are shown below.
8LiH + Al2Cl6→2LiAlH4+6LiCl
2BeCl2+LiAlH4→2BeH2+LiCl+AlCl3
New answer posted
a year agoContributor-Level 10
This is a long answer type question as classified in NCERT Exemplar
Compound A reacts with water to form compound B. So, the compound A is calcium oxide. When water is added to calcium oxide, calcium hydroxide is formed. It is lime water. The compound gives a milky appearance which is compound C. The compound C is calcium carbonate. On passing, excess carbon dioxide milkiness disappears due to the formation of compound D. The compound is calcium hydrogen carbonate. The reactions are as follows:
CaO+H2O→Ca (OH)2
Ca (OH)2+CO2→CaCO3
Ca (OH)2+CO2+H2O→Ca (HCO3)2
New answer posted
a year agoContributor-Level 10
This is a long answer type question as classified in NCERT Exemplar
As the size of metal ions increases, the stability of peroxides and superoxides increases. Peroxide and superoxide ions combine with a large size of alkali metals. Lithium forms monoxide, sodium forms peroxide and potassium, rubidium and caesium forms superoxide.
Li+O2→Li2O
Na+O2→Na2O2
K+O2→KO2
New answer posted
a year agoContributor-Level 10
This is a long answer type question as classified in NCERT Exemplar
(i) The alkali metals dissolve in liquid ammonia and give a blue solution, which is conductive in nature. A solution of sodium in liquid ammonia at -30C conducts electricity. The ammoniated electrons are responsible for the blue color of the solution as they absorb energy in the visible region of light and impart blue color to the solution. Both the ammoniated cations and ammoniated electrons are responsible for the electrical conductivity of the solution.
Na + (x+y)NH3→ [Na (NH3)x]+ + [e (NH3)y]−
(ii) The blue color changes to bronze color in concentrated solution
New question posted
a year agoNew answer posted
a year agoContributor-Level 10
This is a long answer type question as classified in NCERT Exemplar
(i) Alkaline earth metal compounds are less ionic than alkali metals because of small size and more effective nuclear charge.
(ii) Oxides of alkali metals are more basic than alkaline earth metals. This are water soluble and highly exothermic. The hydroxides of alkaline earth metals are less basic than alkali metals.
(iii) Alkaline earth metals give oxosalts. The reactivity of alkali metals is faster than the reactivity of alkaline earth metal. The reactivity of alkaline earth metal is less due to small size and more effective nuclear charge.
(iv) The oxo salts of alka
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