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Correct option is (c) 7, 8, 9

The best I can explain: Metals of the GROUP 7, 8 and 9 do not form hydrides under standard temperature and PRESSURE and this region of the periodic table is called HYDRIDE GAP. So the hydride gap is related to group 7, 8 and 9.

Correct option is (d) precise

Easiest EXPLANATION: Electron precise HYDRIDES are the hydrides which have an exact NUMBER of electrons, that are needed to form normal covalent bonds. Few examples are the hydrides of group 14 like METHANE, SILICON hydride etc.

Right answer is (d) ammonia

Explanation: ELECTRON rich hydrides are the hydrides which have a greater number of electrons than required to FORM normal covalent BONDS. Examples are the hydrides of group 15, 16 and 17, the excess electrons in these hydrides, are present as lone pairs of electrons.

The correct answer is (a) true

To EXPLAIN: Aluminium hydride is a molecular hydride, because it does not have a REQUIRED number of electrons to form the NORMAL covalent bonds. So, aluminium hydride is also called as an electron-deficient hydride, THEREFORE the above STATEMENT is true.

Right answer is (b) ionic hydrides

For explanation: Ionic hydrides are FORMED by elements of GROUP 1 and 2 EXCEPT beryllium and magnesium, by heating them in hydrogen. They are white colourless CRYSTALLINE solid having a high melting point and boiling point and they are easily decomposed by water, carbon dioxide or Sulphur dioxide.

The correct ANSWER is (b) p- block elements

The explanation is: Molecular HYDRIDES are also called as covalent hydrides and they are FORMED by elements of p-block those having higher ELECTRONEGATIVITY than hydrogen. They are again divided into ELECTRON deficient hydrides, electron precise hydrides and electron rich hydrides.

Right answer is (a) true

To explain I would say: The compounds of hydrogen with METALS and nonmetals are called hydrides and their Oxidation state is -1. The examples are sodium HYDRIDE, calcium hydride, magnesium hydride ETC. There are many types of hydrides like ionic hydrides, molecular hydrides covalent hydrides etc.

The correct option is (c) Ionic hydrides

Explanation: Ionic hydrides are very strong REDUCING AGENTS. ALKALI metal hydrides are used for making LITHIUM aluminium hydride, sodium Boron hydride etc and they are ALSO used for removing last traces of water from organic compounds.

Correct option is (b) polymeric hydride

For explanation I would SAY: Polymeric hydrides are formed by elements having ELECTRONEGATIVITY in the range of 1.4 to 2.0. Examples of polymeric hydrides are (BEH2)n, (AlH3)n etc. They are joined to each other through HYDROGEN bonding in order to FORM a larger unit.

Correct option is (b) H^–

For explanation: In COMPLEX hydrides like LITHIUM aluminium hydride or lithium sodium hydride, the hydrogen ACTS as a ligand and it is attached to the central ATOM in complex hydrides, which are salt-like substances.

The correct choice is (b) hydrogen

For explanation I WOULD say: Hydrogen is used in the MANUFACTURE of synthetic petrol, that is why heating dihydrogen with coal and HEAVY oils under the very HIGH pressure and presence of CATALYST we can manufacture synthetic petrol.

Correct choice is (a) it is USED in the MANUFACTURE of SYNTHETIC petrol

The explanation: The correct statement of the incorrect statements are; the dihydrogen is used as a reducing agent in the EXTRACTION of metals, it is used in a fuel cell for GENERATING electrical energy and liquid hydrogen is used as rocket fuel.

Right answer is (C) hydrogen

To explain: In the formation of 2 moles of sodium hydride from TWO moles of sodium and ONE mole of hydrogen, the hydrogen acts as an OXIDISING agent. An oxidizing agent gains electrons from the other molecule and reduces itself.

The correct choice is (B) METHANOL

Easy explanation: In the presence of Cobalt, one mole of carbon monoxide in gaseous state combines with 2 moles of the hydrogen molecule in a gaseous state in ORDER to form one mole of methanol in a LIQUID state. Hydrogen is USED in the manufacture of methanol.

Right option is (c) hydrogenation

Explanation: In presence of Nickel, as a CATALYST at the TEMPERATURE of 400 DEGREES Kelvin, vegetable oil is converted into vegetable ghee in presence of HYDROGEN and this process of transformation of oil into ghee is known as hydrogenation.

Right answer is (C) 673 Kelvin

The explanation: At 673 Kelvin and 200 atmospheric pressure, one mole of nitrogen combines with three moles of hydrogen in presence of iron and molybdenum in ORDER to form 2 moles of ammonia and the ENTHALPY CHANGE is 92.6 KJ per Mol, the enthalpy here change is negative.

Correct choice is (a) true

For explanation I would say: The inertness of dihydrogen comparatively at 27 degree-celcius, is because of its high bond energy of the HYDROGEN bond. Therefore we can say the reactions INVOLVING dihydrogen OCCUR at high temperatures only.

Correct CHOICE is (d) heavier than air

For explanation: Physical properties of dihydrogen include that it is COLOURLESS, odourless, tasteless, COMBUSTIBLE gas. It is LIGHTER than air and insoluble in WATER and is also neutral to Litmus. Therefore heavier than air is not a property of dihydrogen.

The CORRECT CHOICE is (b) false

The explanation: Reduction is a process of gain of electrons and oxidation is a process of loss of electrons. In the electrolysis of acidified water, the reduction occurs at the cathode and oxidation occurs at the anode, the OVERALL process is REGARDED as ionization in electrolysis.

The correct choice is (b) salt water

The best I can explain: A Brine SOLUTION is nothing but water that has dissolved salt in it HYDROGEN is OBTAINED as a byproduct in the manufacture of sodium hydroxide and CHLORINE by the electrolysis of brine solution (salt water).

The correct CHOICE is (d) iron and steam

The explanation is: In Lane’s process from superheated steam, iron filings are PASSED over and heated to about 1023 to 1073 Kelvin when hydrogen is formed. The concerned REACTION is 3FE + 4H2O → Fe3O4 + 4H2 at 1023-1073 K.

The correct OPTION is (c) Electrolysed with barium hydroxide solution

For explanation I WOULD say: Highly pure dihydrogen (H2) that is greater than 99.95% is obtained by electrolysis in warm aqueous barium hydroxide (BaOH(aq)) solution between Nickel ELECTRODES (Ni). This is one of the processes of COMMERCIAL PRODUCTION of hydrogen.

The CORRECT option is (b) SODIUM, zinc, and oxygen

To explain I would say: When zinc is REACTED with sodium hydroxide in the presence of heat Sodium zincate and HYDROGEN are FORMED the chemical formula of sodium zincate is Na2ZnO2. Therefore Sodium Zincate is made of sodium, zinc, and oxygen.

Correct ANSWER is (a) True

For explanation: In the process of preparation of DIHYDROGEN, pure zinc is not USED because it REACTS slowly. Some impurities PRESENCE increases the rate of reaction due to the formation of electrochemical couples.

Right ANSWER is (d) Carbon MONOXIDE and hydrogen

The explanation: The MIXTURE of carbon monoxide and hydrogen produced by a synthetic GAS is KNOWN as water gas. This is from the water gas shift reaction, which was created by a physicist from Italy. Water gas is made by blowing steam through white-hot coke.

Correct CHOICE is (a) TRITIUM

Explanation: Tritium has the GREATEST relative atomic mass than that of DEUTERIUM and PROTIUM. The relative atomic mass of protium, deuterium, and tritium are 1.0078, 2.0141 and 3.016 respectively. They do not have equal mass.

Right answer is (a) 0.33s

The best I can explain: Molecular hydrogen in presence of electric ARC is CONVERTED into ATOMIC hydrogen. The enthalpy change for the reaction is 105.4 kcal/mol. This NEWLY formed atomic hydrogen is very reactive and its half-life period is 0.33 seconds.

The correct option is (B) HEAVY hydrogen

The best explanation: Deuterium is one of the two stable isotopes of Hydrogen (the other one being the PROTIUM), it is known as heavy hydrogen as it has one neutron and one proton. The radioactive ISOTOPE of hydrogen is tritium.

The correct answer is (c) tritium has a greater BOILING point than that of protium

Easy explanation: The boiling points of tritium are greater than that of DEUTERIUM and that is greater than that of HYDROGEN. The boiling points in kelvin of hydrogen, deuterium, and tritium are respectively 20.39, 23.67 and 25.

Right CHOICE is (a) true

Easy EXPLANATION: The above statement is true because deuterium has a GREATER boiling point than that of hydrogen and TRITIUM has a greater boiling point than that of deuterium. The boiling points of tritium, deuterium, and protium are 20.62, 18.73 and 13.96 in Kelvin respectively.

The correct ANSWER is (a) true

The EXPLANATION: Yes, the above STATEMENT is true because protium has a relative abundance greater than that of tritium. The relative abundance of protium is 99.98%, the relative abundance of deuterium as 0.0156% and tritium is 10-15%.

The correct CHOICE is (a) helium

To explain: Hydrogen exists in the form of three ISOTOPES namely protium, deuterium and TRITIUM. The atomic numbers of all the three isotopes of Hydrogen are same i.e. 1, but their symbols, RELATIVE atomic mass, density, etc vary.

Correct answer is (a) protium

To explain: Among the THREE ISOTOPES of Hydrogen; protium, deuterium and tritium, a radioactive isotope is tritium and it emits BETA RAYS and its half-life is 12.33 year. The other two isotopes protium deuterium are non Radioactive.

The correct answer is (b) false

To explain I would SAY: The loss of electrons from hydrogen atom results in the hydrogen nucleus that is H^+ of the size 1.5 X 10^-3 pm and it is extremely small when COMPARED to a normal at atomic and IONIC sizes that are around 50 to 200 pm.

The correct answer is (a) high

The best I can explain: Though hydrogen is PLACED in the FIRST group which is of alkali metals, it has a very high ionization ENTHALPY this is because it has a characteristic of a halogen as WELL. We can say that hydrogen is an alkali metal and a halogen at a TIME.

The correct choice is (c) non-metal

Explanation: HYDROGEN is a nonmetal DENOTED by the symbol “H”, but it is placed in the first GROUP, which consists of metals. This is because of the outer shell configuration of hydrogen and that it’s valency is 1. It’s highly electronegative in NATURE.