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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 1951. |
When zinc metal is treated with a dilute solution of a strong acid, a gas is evolved, which is utilised in the hydrogenation of oil. Name the gas evolved. Write the chemical equation of the reaction and also write a test to detect the gas formed. |
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Answer» SOLUTION :When zinc reacts with DILUTE solution of strong solution of strong acid, it forms salt and hydrogen gas is evolved. `Zn + 2HCl rarr ZnCl_(2)+H_(2)` When a BURNING splinter is BROUGHT near the mouth of the TUBE , the gas burns with a pop sound. |
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| 1952. |
What is meant by displacement reaction? Which metal amongst the Fe and Cu is more reactive? Why? |
| Answer» Solution : The REACTION in which more reactive metal DISPLACES a less reactive metal from its salt solution or can displaces from its molten state is called displacement reaction. Amongst, FE and Cu, Fe is more reactive than Cu, because reactivity of Fe is more than Cu. | |
| 1953. |
Why are carbon and its compounds used as fuels for most applications ? |
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Answer» Solution :When CARBON is burnt in the presence of AIR of OXYGEN, it forms carbon dioxide and WATER with a release of a large amount of heat and light. `C(s)+O_(2)(g)toCO_(2)(g)+"Heat"+"Light"` When carbon and its compounds are burnt, additional heat energy is not required for consistent BURNING. Hence, carbon and its compounds are used as fules for most applications. |
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| 1954. |
What does one mean by exothermic and endothermic reactions ? Give examples. |
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Answer» Solution :CHEMICAL reactions that release ENERGY in the form of HEAT, light, or sound are called exothermic reactions. EX : `C(G)+O_(2)(g) to CO_(2)`+HeatEnergy Reactions that absorb energy or require energy in order to proceed are called endothermic reactions. `N_(2)(g)+O_(2)(g) overset("heat") to 2NO` |
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| 1955. |
Use Mendeleev's Periodic Table to predict the formulae for the oxides of the following elements: (i) K (ii) C(iii) AI (iv) Si (v) Ba |
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Answer» Solution :(i) The element K is in group I of Mendeleev.s Periodic Table in which the general formula of the oxides of ELEMENTS is `R_2O`, therefore, the formula of oxide of K will be `K_2O`. (II) The element C is in group IV of Mendeleev.s periodic table in which the general formula ofthe oxides of elements is `RO_2`, therefore, the formula of oxide of C will be `CO_2`. (iii) The element Al is in group III of Mendeleev.s Periodic Table in which the general formula of the oxides of elements is `R_2O_3` , therefore, the formula of oxide of Al will be `Al_2O_3` (iv) The element Si is in group IV of Mendeleev.s Periodic Table in which the general formula of the oxides of elements is `RO_2`, therefore, the formula of oxide of Si will be `SiO_2`. (V) The element BA is in group II of Mendeleev.s Periodic Table in which the general formula ofthe oxides of elements is RO, therefore, the formula of oxide of Ba will be BaO . |
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| 1956. |
Write the balanced chemical equation and name the products when one mole of methane reacts with two moles of Cl_2. |
| Answer» SOLUTION :`underset("METHANE")(CH_4) + underset("chlorine")(2Cl_2) to underset("dichloromethane")(CH_2Cl_2) + underset("HYDROGEN chloride")(2HCL)` | |
| 1957. |
Which of the following methods is not used for preparing a salt? |
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Answer» reaction between an ACID and a base |
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| 1958. |
Write the changes at the electrodes and in the cell during the purification of copper by electrolysis . |
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Answer» Solution :(i) `Cu^(2+) (aq) +2e^(-) to Cu ` (METAL) (II) Cu (metal ) `to Cu^(2+)(aq) +2e^(-)` No NET change in the CELL |
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| 1959. |
Which of the following sets of quantam numbers is correct for an electron in 3d orbitals |
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Answer» 3,0,0, `+(1//2)` |
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| 1960. |
Which of the following is a non-directionalbond? |
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Answer» COVALENT |
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| 1962. |
Write the IUPAC name of the compoundCH_3 - CH_2 - CH_2 - COOH |
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Answer» Solution :(a) There are 4 C atoms in the chain involving-COOH group, therefore, the ROOT WORD is .but.. (b) Only C-C BONDS appear between C atoms in the chain, therefore, primary suffix is .ane.. THUS, Base name = root word + primary suffix = but + ane = butane (c) There is --COOH group in the chain, therefore, secondary suffix is .OIC acid.. Thus, the IUPAC name of the given compound is derived as: Butane named -e + Secondary suffix Butane - e + oic acid = Butanoic acid |
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| 1963. |
Which of the following is not a property of acids? |
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Answer» all acids have a sour TASTE |
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| 1964. |
What is meant by isomers? Draw the structures of two isomers of butane, C_(4)H_(10). Explain why are cannot have isomers of first three members of alkane series. |
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Answer» Solution :Isomers are compounds having the same molecular formula but DIFFERENT STRUCTURES. The two isomers of butane, `C_(4)H_(10)` are: `H-UNDERSET(H)underset(|)OVERSET(H)overset(|)C-underset(H)underset(|)overset(H)overset(|)C-underset(H)underset(|)overset(H)overset(|)C-underset(H)underset(|)overset(H)overset(|)C-H`  Since branching is not possible, isomers are not possible for the first three members of alkane series. |
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| 1966. |
Two monovalent metals A and B are treated with dilute sulphuric acid. A liberates hydrogen and metal B does not. Predict the half-cell reactions and cell representation when these metals are coupled with H-electrode. Justify your answer with respect to standard electrode potential |
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Answer» Solution :(i) COMPARISON of electropositivity of A and B with HYDROGEN. (ii) Identification of ANODE and cathode of the electrochemical cells. (III) Half-reactions that take place at the electrodes of the respective cells. |
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| 1967. |
What do you mean by double circulation of blood? |
| Answer» SOLUTION :BLOOD PASSES through the heart twice for each CYCLE through the body. | |
| 1968. |
What is the precentage of gold present in ' Hall mark ' gold ? |
| Answer» SOLUTION :`91.67%` | |
| 1969. |
Which of the following reactions is characterised by an yellow product ? |
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Answer» `Zn+H_(2)SO_(4)toZnSO_(4)+H_(2)` |
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| 1970. |
What is a thermite reaction (process) ? |
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Answer» SOLUTION :The PROCESS in which metals are obtained by the reduction of their oxides by ALUMINIUM powder. For example, manganese dioxide is HEATED with aluminium powder to GET manganese. `3MnO_(2)+4Aloverset("Heat")to3Mn+2Al_(2)O_(3)`. |
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| 1971. |
Which of the following is a decomposition reaction ? |
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Answer» `NAOH + HCl to NACL +H_(2)O` |
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| 1972. |
When an alkali metal combines with halogen, it will form |
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Answer» ALWAYS covalent BOND |
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| 1973. |
Which one is the formula of baking soda?Na_(2)CO_(3)NaOHKHCO_(3)NaHCO_(3) |
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Answer» `Na_(2)CO_(3)` |
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| 1974. |
Which of the following has an equal number of neutrons and protons? |
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Answer» hydrogen |
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| 1975. |
What is the number of carbon compounds estimated approximately? |
| Answer» SOLUTION :THREE MILLION | |
| 1976. |
What is the chemical reaction taken place in the tarnishing of silver anklet? |
| Answer» Solution :The LUSTROUS white colour of the silver anklet SLOWLY changes into slightly blackcolour.It is due to the formation of silver SULPHIDE`(Ag_(2)S)` as a result of the reaction between silver and hydrogen sulphide in the air. | |
| 1977. |
Which cation in the given pair will be discharged first during electrolysis under similar conditions ? Na^(+) and Mg^(2+) |
| Answer» SOLUTION :`MG^(2+)` | |
| 1978. |
Which cation in the given pair will be discharged first during electrolysis under similar conditions ?Fe^(2+) and Cu^(2+) |
| Answer» SOLUTION :`CU^(2+)` | |
| 1979. |
Which cation in the given pair will be discharged first during electrolysis under similar conditions ? H^(+) and Cu^(2+) |
| Answer» SOLUTION :`CU^(2+)` | |
| 1980. |
Which cation in the given pair will be discharged first during electrolysis under similar conditions ? Cu^(2+) and Ag^(+) |
| Answer» SOLUTION :`AG^(+)` | |
| 1981. |
Write one word term of the following (i) Water soluble base (ii) A substance which dissociates on dissolving in water to produce hydrogen ions. [H^+ (aq) ions] (iii) A reaction between an acid and a base to form salt and water. (iv) A substance which dissociates on dissolving in water to produce hydroxide ions [OH^(-) ions] |
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Answer» Solution :(i) ALKALI (II) ACID (iii) Neutralization reaction (IV) BASE |
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| 1982. |
Which cation in the given pair will be discharged first during electrolysis under similar conditions ?Fe^(2+)and Zn^(2+) |
| Answer» SOLUTION :`FE^(2+)` | |
| 1983. |
Which amongst the following contains double covalent bond? |
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Answer» `C_(2)H_(2)` 
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| 1984. |
What are root words? |
| Answer» SOLUTION :ROOT words is the basic UNIT which describes the CARBON skeleton. It gives the number of carbon atoms present in the present chain of the compound and the pattern of their arrangement. | |
| 1985. |
What is a catalyst? Give examples. |
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Answer» Solution :CATALYST is a substance in the presence of which a reaction proceeds with HIGHER RATE but itself remains unaffected. EXAMPLES : Nickel, palladium, iron, etc. |
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| 1986. |
Write the formulae of two homologues of ethane. |
| Answer» SOLUTION :`CH_4` is LOWER HOMOLOGUE and `C_3 H_8`is HIGHER homologue of ETHANE `(C_2H_6)` . | |
| 1987. |
Which of the following statements is not a correct statement about the trends when going from left to right across the periods of periodic table: |
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Answer» The elements become less metallic in nature. |
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| 1988. |
Which functional group is present in meyhyl ethanoate ? |
| Answer» Answer :D | |
| 1989. |
What are amphoteric oxides ? Give two examples of amphoteric oxide with balanced chemical equation. |
Answer» Solution : An oxide which reacts with ACIDS as well as bases to produce SALT and water is CALLED amphoteric oxide.
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| 1990. |
Which one of the following can be used as acid-base indicator by a visually impared student ? |
| Answer» Solution :Vanilla essence | |
| 1991. |
You are given the following materials : {:((i), "Iron nails",, (ii), "Copper sulphate solution"),((iii), "Barium chloride solution",, (iv), "Copper powder"),((v), "Ferrous sulphate crystals",, (vi), "Quick lime"):} Identify the type of chemical reaction taking place when : (a) Barium chloride solution is mixed with copper sulphate solution and a white precipitate is observed. (b) On heating, copper powder in air in a china dish, the surface of copper powder becomes black. (c) On heating green ferrous sulphate crystals, reddish brown solid is left and a gas having smell of burning sulphur is noticed. (d) Iron nails when left dipped in blue copper sulphate solution becomes brownish in colour and blue colour of copper sulphate solution fades away. |
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Answer» Solution :(a) The reaction is double displacement in nature. `{:(BaCl_(2)(aq) + CuSO_(4)(aq)to, BaSO_(4)(s) + CuCl_(2)(aq)),(,"(White ppt.)"):}` (b) It is an example of combination reaction. `{:(2Cu(s) + O_(2)(g) to, 2CuO(s)),("""(in air)", "Copper (II) oxide"),(,"""(Black)"):}` (c) The green crystals of ferrous sulphate have the chemical formula`FeSO_(4).7H_(2)O.` Upon heating, they lose molecules of water of crystallisation and it is an example of dehydration reaction. `underset("(Green)")(FeSO_(4)).7H_(2)Ooverset("heat")to FeSO_(4) + 7H_(2)O` Upon further heating, ferrous sulphate undergoes decomposition reaction as follows : `{:(2FeSO_(4)(s)overset("heat")to, Fe_(2)O_(3)(s) + SO_(2)(g) + SO_(3)(g)),(,"Ferric oxide(Reddish brown)"):}` Both the gases evolved have the small of burning sulphur. (d) This happens because of displacement reaction. IRON displaces copper from copper sulphate solution. Brownish COATING of copper GETS DEPOSITED on the iron nails. As the concentration of coppe sulphate in the solution decreases, the blue colour of the solution slowly fades. `{:(Fe(s) + CuSO_(4)(aq) to, FeSO_(4)(aq) + Cu(s)),(,"""(Brownish)"):}` |
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| 1992. |
What is the concentration of hydrogen ions [H^(+)(aq)] in a solution when pH = 0? |
| Answer» SOLUTION :`[H^(+)]=10^(-PH)=10^(-0)=1"mol"//L` | |
| 1993. |
What are the ions present in these compounds? |
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Answer» Solution :IONS PRESENT in `Na_2O : NA^+` and `O^(2-)` Ions present in `MgO : MG^(2+)` and `O^(2-)` |
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| 1994. |
What will be the action of the following substances on litmus paper ? Dry HCl gas, Moistened NH_(3) gas, Lemon juice, carbonated soft drink, Curd, Soap solution. |
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Answer» Solution :`ul("Substance") ul("Action on LITMUS PAPER")` Dry HCl gas No change MOISTENED `NH_(3)` gas Turns red to blue Lemon juice Turns blue to red Carbonated sof drink Turns blue to red CURD Turns blue to red Soap solution Turns red to blue |
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| 1995. |
Which compound is used to detect the formation of carbon dioxide gas ? |
| Answer» SOLUTION :CALCIUM HYDROXIDE `(Ca(OH)_(2))` | |
| 1996. |
What type of bond is formed when two atoms combine by sharing of electrons ? |
| Answer» SOLUTION :COVALENT BOND | |
| 1997. |
The value of molar volume is …………….. . |
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Answer» 22.4 ml |
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| 1998. |
Which of the following is not a base according to any of the theories ? |
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Answer» `Mg(OH)_(2)` |
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| 1999. |
What do you observe when you drop a piece of sodium into ethanol? Name the gas evolved. How do you test this gas? Write the chemical equation for the reaction. |
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Answer» Solution :When a piece of sodium metal is dropped in ethanol, it reacts vigorously with the evolution of hydrogen GAS. sodium + ethanol → sodium ETHOXIDE + hydrogen `2Na_((s)) + 2C_2 H_5 OH_((l)) to2C_2 H_5ONa_((l)) + H_(2(g))` Hydrogen gas can be TESTED by exposing a burning matchstick to the gas, hydrogen burns with a POP sound and puts off the match stick. |
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| 2000. |
When CaO is added to water taken in a beaker, rise in temperature is observed. However, when Ba(OH)_(2) is mixed with NH_(4)Cl, a fall in temperature is observed. Why? |
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Answer» Solution :Reaction of CaO and water is an exothermic reaction. So, rise in temperature is observed. `UNDERSET("Calcium oxide")(CaO(s))+H_(2)O(l)rarrunderset("Calcium HYDROXIDE")(Ca(OH)_(2)(aq))+"Heat"` Reaction of `Ba(OH)_(2)andNH_(4)Cl` is an endothermic reaction and hence FALL in temperature is observed. `underset("hydroxide")underset("Barium")(Ba(OH)_(2))+underset("chloride")underset("Ammonium")(2NH_(4)Cl)+"Heat"rarrunderset("chloride")underset("Barium")(BaCl_(2))+underset("hydroxide")underset("Ammonium")(2NH_(4)OH)` |
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