1) Name or state with reference to hydrogen-- the first element of the periodic table.
Name/state:
a) The period of the periodic table to which the element hydrogen belongs.
b) The two subgroups of the periodic table in which hydrogen can be placed.
c) The element in period 3 which is electropositive shows similarity to hydrogen.
d) The element in period 4 which is electronegative and shows similarity to hydrogen.
e) An element in period 2 which has the same atomicity as hydrogen.
f) An element which combines both hydrogen and halogens forming covalent compounds.
g) An electrovalent compound formed from an element in period 3 and hydrogen.
h) A Covalent gaseous compound formed from an element in period 3 and hydrogen
i) A covalent gaseous compound formed from an element in group IV A and hydrogen
j) An oxide of hydrogen which is neutral in nature.
k) The number of shared pairs of electrons in a diatomic molecule of hydrogen.
l) A non metallic element in group IA of the periodic table.
2) Complete the following sentence by filling in the blanks with appropriate word/s
a) The first element hydrogen of the periodic table shows similarity with___ metals of group VII A.
b) Hydrogen shows electropositive character. Elements in group 1A are considered electropositive since they have a tendency to____one electron from its valency shell.
c) Hydrogen also shows electronegative character. Elements in group VII A are considered electronegative since they have a tendency to____ one electron forming an electronegative element.
d) The electronic configuration of the element in period 3 which has the same number of valence electrons as hydrogen.
e) The element in group 1A which has one electron less than the noble gas present in Period 1 of the periodic table is___.
f) Hydrogen is a diatomic molecule which has two atoms linked by a____ covalent bond. The element in group VII A which is also diatomic and exists in the liquid state at room temperature is______.
g) Halides of hydrogen and alkali metals yield____ ions in aqueous solution. During electrolysis these ions are discharged at the negative electrode i.e., cathode.
3) Give reasons for the following:
a) Hydrogen can be positioned in group 1A and group VII A of the periodic table.
b) Hydrogen can be represented as H¹⁺or as H¹⁻
4) MATCH the Column
Column -I
A) Lavoisier in 1783 established the name hydrogen
B) hydrogen does not occur
C) hydrogen is present in traces in
D) A compound one ninth by mass of which is hydrogen in the combined state is
Column II
a) the atmosphere around Sun and stars
b) water
c) meaning water producer
d) in the free state on earth
5) Hydrogen is prepared from cold water, boiling water or steam by reaction with certain metals involving potassium, sodium, calcium, magnesium, aluminium, zinc, Iron. Complete and balance the equations for the reactions of the above metals with metals with water by substituting the correct symbols in each case.
A) Reaction with cold water
1) X + H₂O -> XOH +H₂ [X burns in air with a lilac flame]
2) Y + H₂O -> YOH + H₂ (Y burns in air to the golden yellow flame)
3) Z + H₂O -> Z(OH)₂ + H₂ (Z burns in air with a brick red flame)
B) Reaction with boiling water or steam:
1) Q+ H₂O -> QO + H₂ (QO is a basic oxide)
2) R + H₂O -> RO + H₂ (RO is an amphoteric oxide)
3) S + H₂O -> S₂O₃ + H₂ (S is a trivalent metal)
4) T + H₂O <=> T₃O₄ + H₂ (reaction of T with steam is reversible)
6) hydrogen is also prepared by the action of metals on dilute acids and on alkalis. The metal is converted to its salt in gaseous hydrogen is liberated.
Complete and balance the equations for the conversations on the following metals to their salts using an acid or an alkali.
a. Mg + ___ + ___(magnesium chloride) + H₂
b. Al + ___ -> ____(aluminium sulphate)+H₂.
c. Fe+ ___ -> ___(ferrous chloride) +H₂
d. Zn + ___ ->___(sodium zincate) + H₂
e. Pb+ __ ->___(sodium plumbate) +H₂
f. Al+ __ -> __ (Sodium aluminate) + H₂
g. Al + ___ -> ___(Potassium aluminate) + H₂
7) Give reason for the following:
a) Sodium and potassium are not preferred as the starting metals in the preparation of hydrogen from cold water.
b) Amalgamated sodium can be used in place of sodium in the above preparation.
c) Reaction of magnesium or aluminum with boiling water is comparatively slow and the reaction later comes to a stop.
d) The reaction in (c) above can be made proceed again by passage of steam over the red hot metal.
e) Reaction of magnesium with water moves in the forward direction only while that a iron with water(steam) is reversible reaction.
f) Dilute nitric acid is generally not used in the preparation of hydrogen from metals, however, magnesium reacts with very dilute nitric acid at low temperatures liberating hydrogen.
g) Dilute acids react with metals liberating hydrogen, even then lead is not used in the reaction with dilute hydrochloric or sulphuric acid.
8) Name the following:
a) A metal which reacts exclusively with cold water liberating hydrogen.
b) A metal alloyed with sodium to give amalgamated sodium.
c) A metal which reacts very slowly with boiling water to liberate hydrogen.
d) A trivalent metal which displaces hydrogen from dilute sulphuric acid.
e) The salt formed when iron reacts with dilute hydrochloric acid displacing hydrogen from it
f) A metal which reacts with dilute hydrochloric acid to form a salt insoluble in cold water but soluble in hot water.
g) The salt formed when zinc reacts with caustic Potash liberating hydrogen.
h) A metal other than magnesium which reacts with very dilute nitric acid liberating hydrogen.
i) A metal which react with cold water forming a turbid solution.
j) Two metals which do not displace hydrogen from dilute acids.
9) In the Laboratory Preparation of Hydrogen
a) Complete and balance the equation for the preparation of hydrogen. ___(metal) +__(dil) --> __(salt) + H₂
**Give reasons for the following:
b) Granulated zinc is preferred to pure zinc for the reaction with dilute acid.
c) The initial gas bubbles of hydrogen are allowed to escape out before the actual collection of hydrogen gas.
d) highly electropositive metals are not used in place of zinc in the preparation.
e) Concentrated hydrochloric acid is not preferred to dilute acid for reaction with zinc in the laboratory preparation.
f) A naked flame is never brought near the apparatus used in the laboratory preparation.
g) The lower end of the thistle funnel should dip below the level of the dilute acid in the flask.
h) Traces of copper(II) sulphate may be added to the reaction medium.
i) Hydrogen gas prepared in the laboratory has a peculiar smell.
j) Hydrogen is lighter than air, even then it is not collected over air, but by downward displacement of water.
10) Pure hydrogen is prepared by passage of the gas through various solutions which respectively absorb each impurity. Match the impurity with the solution which absorbs it.
IMPURITY
a) Arsine (AgH₃)
b) Phosphine (PH₃)
c) hydrogen sulphide(H₂S)
d) Nitrogen dioxide(NO₂)
e) Sulphur dioxide (SO₂)
f) moisture
REMOVED BY
i) potassium hydroxide solution
ii) fused calcium chloride
iii) silver nitrate solution
iv) lead nitrate solution
**Preparation Of Hydrogen- Industrial Method:::
11) Complete the table pertaining to the production of hydrogen by the Bosch process involving three main steps...
STEP 1 Production of water gas
X + H₂O ----> XO + H₂ ∆
• Equation: ____________
• X is white/red hot _______
• Temperature of the reaction__°C
• Reaction involves passage of ____ (water/steam) over X.
• Reaction is___ (exothermic/ endothermic).
• Resultant product of the reaction is water gas is a mixture of_____(XO) and hydrogen in the ratio ___:_____.
Step II Reduction of steam to hydrogen by XO :
XO + H₂ + H₂O ----> XO₂+ 2H₂ ∆
• equation _______.
• the reactants are water gas and ___ (Limited/Excess)steam.
• temperature of the reaction is around_____°C.
• the catalyst used is ___(Z₂O₃)
• The Catalyst also used other than the one used in (d) above is ____
• ____(XO) is ____ (oxidised/ reduced) to ____(XO₂) with the further yield of hydrogen in the reaction in Step II.
• reaction in step II is ______ (exothermic/endothermic).
Step III: Removal of carbon monoxide and carbon dioxide from the mixture ::
Using X,Y and Z how are the gas separated.
X= potassium hydroxide
Y= water
Z= Ammoniacal Cuprous chloride
Solution gas absorbed equation
----------- ------------------- -------
X= KOH
Y= water
Z= Ammoniacal CuCl₂
12) A method other than the one used above for manufacture of hydrogen involves electrolysis of neutral liquid (X) as the starting reactant.
a) name the neutral liquid.
b) give the equation for the same.
c) name the electrode at which is liberated.
d) state the reason for acidification of the neutral liquid.
e) Name another solution which on electrolysis liberates hydrogen as a by-product.
13) Using hydrogen as one of the reactants how would you obtain, show the equations
a) a neutral liquid using a neutral gas.
b) an acidic gas using another acetic gas.
c) A basic gas using an unreactive gas.
d) A acidic gas using vapours of a non metal.
e) A hydride using a monovalent active metal.
14) Hydrogen reduces certain metallic oxide to free metals. Give an equation of each of the following reactions.
write the equations for Reduction
a) A black basic oxide.
b) A yellow amphoteric oxide.
c) An oxide of iron.
15) NAME THE FOLLOWINGS:
a) the condition in which equal volumes of hydrogen and chlorine react slowly producing hydrogen chloride.
b) the catalyst and the promoter used in the conversion of Nitrogen to form Ammonia using hydrogen.
c) the state of sulphur reacts with hydrogen forming hydrogen sulphide.
d) the phenomenon due to which certain metals eg., Palladium adsorb large volumes of hydrogen on their surface.
e) a catalyst used in hydrogenation reactions.
f) a product manufactured using the process of hydrogenation of oils
g) the product of oxidation of hydrogen formed during reduction of zinc oxide by hydrogen.
h) the product formed when pure hydrogen burns in oxygen.
I) a metallic oxide which is not reduced to its metal by hydrogen.
j) two colourless gases one of which is hydrogen which combines under suitable conditions to give another colourless gas.
16) GIVE REASON:
a) Nickel finds application in hydrogenation reaction eg., Hydrogenation of oil.
b) passage of hydrogen through vegetables oils under suitable conditions results in their solidification.
c) Pure hydrogen burns quietly while hydrogen-air mixture does not.
d) hydrogen can separated from a mixture of hydrogen and carbon dioxide by liquification.
17) From the Activity series, NAME THE FOLLOWING:::
a) react violently with water liberating hydrogen.
b) does not react with steam or dilute hydrochloric acid.
c) is a divalent and displaces hydrogen from water.
d) displaces hydrogen from caustic soda but does not react with dil. HCL.
e) displaces hydrogen from dilute nitric acid.
f) does not react with dil. Sulphuric acid but reacts with steam liberating hydrogen.
g) displaces hydrogen from dilute HCl and dilute Sulphuric acid but not from nitric acid.
h) reacts violently when placed in any dilute acid.
I) displaces hydrogen from cold water forming a colourless solution.
j) displaces hydrogen from steam leaving behind an amphoteric residue.
18) GIVE REASON:
a) hydrogen gas can be tested by its from the combustibility in air.
b) If a jar containing hydrogen carbon dioxide mixture is placed over an empty the porous pot, the porous pot gets filled with hydrogen initially.
c) Two gas jars, containing oxygen and the other hydrogen can be identified with the glowing splinter, but not with the moist Litmus Paper.
c) hydrogen finds application as a constituent of important fuels.
d) hydrogen gas was initially used to study weather conditions
e) extraction of certain metals from their oxides may be carried out using hydrogen.
f) Oxy-hydrogen flames used in welding and cutting of metals produces high temperatures.
g) hydrogen finds application in the conversion of palm oil and solid fats.
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