Which of the following hydrides is electron-precise hydride?
(a) B2H6
(b) NH3
(c) H20
(d) CH4
(d) CH4 is an electron precise hydride since there are exact number of electrons to form normal covalent bonds.
Do you expect different products in solution when aluminium (III) chloride and potassium chloride treated separately with (i) normal water (ii) acidified water (iii) alkaline water? Write equation wherever necessary.
Justify the position of hydrogen in the periodic table on the basis of its electronic configuration.
Why does H+ ion always get associated with other atoms or molecules?
(a) Ionisation enthalpy of hydrogen resembles that of alkali metals.
(b) Its reactivity is similar to halogens.
(c) It resembles both alkali metals and halogens.
(d) Loss of an electron from hydrogen atom results in a nucleus of very small size as compared to other atoms or ions. Due to small size it can not exist freely.
Dihydrogen reacts with dioxygen (02) to form water. Write the name and formula of the product when the isotope of hydrogen which has one proton and one neutron in its nucleus is treated with oxygen. Will the reactivity of both the isotopes be the same towards oxygen? Justify your answer.
Which of the following reactions increases production of dihydrogen from synthesis gas?
Saline hydrides are known to react with water violently producing fire. Can C02, a well known fire extinguisher, be used in this case? Explain.
Hydrogen peroxide is obtained by‘the electrolysis of _______.
(a) water
(b) sulphuric acid
(c) hydrochloric acid
(d) fused sodium peroxide
Which of the following statement(s) is/are correct in the case of heavy water?
(a) Heavy water is used as a moderator in nuclear reactor.
(b) Heavy water is more effective as solvent than ordinary water.
(c) Heavy water is more associated than ordinary water.
(d) Heavy water has lower boiling point than ordinary water.
Why does hydrogen occur in a diatomic form rather than in a monoatomic form under normal conditions?
(a) How is dihydrogen prepared from water by using a reducing agent?
(b) Give the industrial use of dihydrogen which depends upon heat liberated when it bums.
What do you understand by the term ‘auto-protolysis of water? What is its significance?
Complete the following chemical reactions.
(i) PbS(s) + H2O2 (aq) ————->
(ii) MnO4– (aq) + H2O2 (aq) ————->
(iii) CaO(s) + H2O(g) ————->
(iv) AlCl3(g) + H2O(l)————->
(v) Ca3N2(S) + H2O(l) ————->
Classify the above into (a) hydrolysis, (b) redox and (c) hydration reactions.
Discuss the principle and method of softening of hard water by synthetic ion-exchange resins.
Write chemical reactions to justify that hydrogen peroxide can function as an oxidising as well as reducing agent.
Which of the following statements are correct?
(a) Metallic hydrides are deficient of hydrogen.
(b) Metallic hydrides conduct heat and electricity.
(c) Ionic hydrides do not conduct electricity in solid state.
(d) Ionic hydrides are very good conductors of electricity in solid state.
Among NH3 H2O and HE, which would you expect to have highest magnitude of hydrogen bonding and why?
Is demineralised or distilled water useful for drinking purposes? If not, how can it be made useful ?
Discuss the consequences of high enthalpy of H-H bond, in terms of chemical reactivity of dihydrogen.
What do you understand by the term ‘auto-protolysis’ of water? what is its significance?
Consider the reaction of water with F2 and suggest, in terms of oxidation and reduction, which species are oxidised/reduced ?
Which gas is evolved when Mg3N2 (Magnesium nitride) is treated with H2O? Give chemical reaction.
Explain the following:
(i) Temporary hardness can remove by boiling
(ii) Soft water lathers with soap but hard water not.
Which of the following equatibns depicts the oxidizing nature of H202?
(a) 2Mn0–4 + 6H+ + 5H202 → 2Mn2+ + 8H20 + 502
(b) 2Fe3+ + 2H+ + H202 → 2Fe2+ + 2H20 + 02
(c) 2I– + 2H+ + H202 → I2 + 2H20
(d) KI04 + H202 → KI03 + H20 + 02
Which of the following statements are not true for hydrogen?
(a) It exists as diatomic molecule.
(b) It has one electron in the outermost shell.
(c) It can lose an electron to form a cation which can freely exist.
(d) It forms a large number of ionic compounds by losing an electron.
Some of the properties of water are described below. Which of them is/are not correct?
(a) Water is known to be universal solvent.
(b) Hydrogen bonding is present to a large extent in liquid water.
(c) There is no hydrogen bonding in the frozen state of water.
(d) Frozen water is heavier than liquid water.
Which of the following statements are correct?
(a) Elements of group 15 form electron deficient hydrides.
(b) All elements of group 14 form electron precise hydrides.
(c) Electron precise hydrides have tetrahedral geometries.
(d) Electron rich hydrides can act as Lewis acids.
How is heavy water prepared? Compare its physical properties with those of ordinary water.
(i)Draw the gas phase and solid phase structure of H202.
(ii) H202 is a better oxidizing agent than water. Explain.
Describe the bulk preparation of dihydrogen by electrolytic method. What is the role of an electrolyte in this process?
