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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.
| 1601. |
Which metals are poor conductors of heat? |
| Answer» SOLUTION :LEAD and mercury are poor conductors of heat. | |
| 1602. |
What is meant by amphoteric oxide ? Give two examples of it and write the equation of its reaction with acid and base. |
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Answer» Solution : Metal oxides which react with both acids and bases to FORMS salt and water are called amphoteric oxides. EXAMPLES: (i) Aluminium oxide `(Al_2O_3)`(ii) Zinc oxide(ZnO) Aluminium oxide REACTS with an acid and a base in the following manner : `Al_2O_3 + 6HCl to 2AlCl_3 + 3H_2O` `Al_2O_3 + 2NaOH to underset("sodium ALUMINATE")(2NaAlO_2) + H_2O` Zinc oxide reacts with an acid and a base in the following manner: `ZnO + 2HCl to ZnCl_2 +H_2O` `ZnO + 2NaOH to underset("sodium ZINCATE")(Na_2ZnO_2) + H_2O` |
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| 1603. |
Why are ionic compounds usually hard? |
| Answer» Solution :In all IONIC COMPOUNDS, their POSITIVE and negative ions are attached to each other by a strong ionic bond. So, they are rigid and hard SOLIDS. | |
| 1604. |
Three elements which are metalloids. |
| Answer» Solution :(i) Boron (B) (II) Silicon (Si) (III) GERMANIUM (GE). | |
| 1605. |
Which of the following contains only one unpaired electron in the valence shell? |
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Answer» `11^(NA)` |
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| 1606. |
When 180 g of glucose is subjected to combusion, the volume of CO_(2) liberated at STP is |
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Answer» `22.4` L |
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| 1607. |
The stable isotope of carbon (C-12) with atomic mass 12 is used as the standard for measuring the relative atomic mass of an element. |
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Answer» |
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| 1608. |
Write the skeletal equation for the following reactions : Methane on burning combines with oxygen to produce carbon dioxide and water. |
| Answer» SOLUTION :`CH_(4)+O_(2)toCO_(2)+H_(2)O`. | |
| 1609. |
Why cannot aluminium be obtained by reduction of its oxide with carbon? |
| Answer» SOLUTION :ALUMINIUM has more AFFINITY for OXYGEN than CARBON. | |
| 1610. |
What is a balanced chemical equation ? Why should chemical equations be balanced ? |
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Answer» Solution :A chemical reaction in which atoms of DIFFERENT elements of reactant and product side are equal then the chemical equation is called balanced chemical equation. Now, ACCORDING to the law of conservation of MASS, matter can neither be created, nor be DESTROYED. Hence in a chemical reaction, mass of reactants should be equal to the mass of products. Number of atoms of each element should be equal on both side of the reaction for keeping mass CONSTANT. Hence, it is essential to balance the chemical equation. |
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| 1611. |
Which of the following gases can be used for storage of fresh sample of oil for a long time ? |
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Answer» CARBON DIOXIDE or OXYGEN |
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| 1612. |
Which of the following is a basic oxide ? |
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Answer» CAO CaO is a basic oxide `CO_(2)` is an ACIDIC oxide `H_(2)O` is an amphoteric and `N_(2)O` is a neutral oxide. |
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| 1613. |
What two characteristics are observed when dilute hydrochloric acid is added to zinc granules? |
| Answer» Solution :The two CHARACTERISTICS observed are EVOLUTION of a GAS and evolution of heat ENERGY. | |
| 1614. |
What is wrong with the following equation? Mg+OrarrMgO Identify the mistake and balance the equation. |
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Answer» SOLUTION :In this EQUATION, oxygen should be in molecular form `(O_(2))` as oxygen exists as BIMOLECULAR GAS `O_(2)`. `2Mg+O_(2)rarr2MgO` |
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| 1616. |
What is called redox reaction (or oxidation - reduction reactions)? Explain it with suitable examples. |
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Answer» Solution :A reaction in which one reactant GETS oxidised and the other reactant gets reduced, then such reaction is called redox reaction (or oxidation – reduction reactions). OR A reaction in which both oxidation and reduction reactions occur simultaneously is called redox reaction (or oxidation - reduction reactions). Examples of redox reaction :  In above reactions, CUO, ZnO and `MnO_(2)` are reduced to Cu, Zn and `MnCl_(2)` respectively while `H_(2)`, C and HCI are oxidised to `H_(2)O, CO` and `Cl_(2)`respectively. Similarly, rusting of iron (corrosion) is also a redox reaction. |
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| 1618. |
Which one of the following is a hetero triatomic molecule? |
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Answer» `H_(2)O` |
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| 1619. |
What is the substance called when it is present in a solution in lesser amount than the amount of the solvent ? |
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Answer» SOLUTION |
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| 1620. |
The valence electronic configuration of an atom is 6s^2 If d-orbital of the penultimate shell contains two unpaired electrons, calculate the atomic number |
| Answer» SOLUTION :Sincethe valence electronic configuration of the atom is `6s^2` and cl-orbital of the penultinute shell CONTAINS TWO UNPAIRED electrons, the electromc configuration is `[Xe]6s^24f^(14)5d^2`Therefore, the atomic NUMBER of the elen1ent is 72. | |
| 1621. |
What would happen to iron railings on the road side if they are not painted? Why does it happen so? |
| Answer» Solution :If the iron railing on the road side is not painted, a brown rust would from on its surface. Because the moist air of the ATMOSPHERE REACTS with iron to form brown flaky substance on its surface. The rust is HYDRATED iron (III) oxide `Fe_2O_3.xH_2O`. | |
| 1622. |
Why are elementsof group 18 unreactive ? |
| Answer» Solution :The ATOMS of the group 18 elementshave stable ELECTRONIC CONFIGURATION in their valence shells and HENCE they are unreactive . | |
| 1623. |
Write the following componentsfor the electrolytic refining of a piece of impure copper : (iii) The electrolyte . |
| Answer» SOLUTION :ELECTROLYTE : An ACIDIFIED solution of COPPER SULPHATE . | |
| 1624. |
Whena chemicalbondis formed, energyisabsorbed . |
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Answer» |
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| 1625. |
Who defined element as basic form of matter that cannot be broken down into simpler substances by chemical reactions? |
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Answer» Wilhelm Weins |
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| 1626. |
When lead nitrate is heated ,the gas liberatedis………..and its colour is …………. |
| Answer» SOLUTION :`NO_(2)` ,REDDISH BROWN | |
| 1627. |
Which element of the second period form most acidic oxide ? |
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Answer» Boron |
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| 1628. |
What is the SI unit of potential difference ? Name the device used to measure the potential difference. |
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Answer» SOLUTION :SI UNIT of potential DIFFERENCE: volts Device used to MEASURE the potentia. difference : Voltmeter |
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| 1629. |
Write the balanced chemical equations for the following reactions : Sodium carbonate on reaction with hydrochloric acid in equal molar concentrations gives sodium chloride and reaction hydrogencarbonate. |
| Answer» SOLUTION :`Na_(2)CO_(3)+HCl toNaHCO_(3)+HCl` | |
| 1630. |
Zinc Blende is concentrated by |
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Answer» CHEMICAL SEPARATION |
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| 1631. |
Which of the following formulae represents a saturated hydrocarbon? C_(n)H_(2n+2), C_(n)H_(2n+1), C_(n)H_(2n), C_(n)H_(2n-2) |
| Answer» Solution :`C_(N)H_(2n+2)` REPRESENTS a saturated HYDROCARBON. | |
| 1632. |
What is valency? Explain the trends of valency for elements in a period and in a group. |
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Answer» Solution :Relative ability of an element to combine with other element is known as a valency. OR The valency is the combining capacity of an atom of an element to acquire noble GAS configuration. Valency depends on the number of valence electrons. The valency of an element is either equal to the number of electrons in the valence shell or equal to eight minus the number of electrons in the valence shell or equal to 18 minus the group number of the element in the modern periodic table. Variation of valency in a period : On moving from left to right in a period, the valency of the elements first increases and then decreases. For example, the valency of elements of the THIRD period are as follows:  Variation of valency in a group: In the modern periodic table, the elements of the same group have the same outer electronic configuration. Hence, all the elements of the same group POSSESS equal number of valence electrons. Therefore, valency of each element remain same. For exampl. 
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| 1633. |
What is meant by blister copper? What is the reason for the formation of blister copper? |
| Answer» Solution :Copper obtained from Bessemer converter by the process of Bessemersiation gets blistertypeappearance. This is CALLED blister copper. During the process of Bessemerisation, `Cu_(2)OandCu_(2)S` REACT to produce copper and `SO_(2)` gas. In this process, copper is obtained in the molten form and then it is solidified. During solidification, `SO_(2)` gas ESCAPES and hence, blister copper is obtained. | |
| 1634. |
Write the combustion reactions of methane |
| Answer» SOLUTION :`CH_4(G) + 2O_2(g) to CO_2(g) + 2H_2O (L) + ` HEAT | |
| 1635. |
What happens when a solution of baking soda is heated? Write chemical equation for the same. Name the product which is reponsible for making the bread or cake spongy and fluffy. |
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Answer» SOLUTION :When BAKING soda is heated, it decomposes to produce sodium carbonate, WATER and `CO_2` gas. `2NaHCO_3 to^(Delta) Na_2CO_3+H_2O+CO_2` `CO_2` gas PRODUCED during the reaction makes the cake or BREAD spongy and fluffy. |
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| 1636. |
What is meant by functional group in an organic compound ? Give the structural formular of the functional groups in (i) Acetic acid (ii) Ethyl alcohol. |
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Answer» Solution :Functional group is an atom or group of ATOMS which DETERMINES properties or ORGANIC compound. (i) `-overset(O)overset(||)(C )-OH` is the functional group present in `CH_(3)COOH` (Acetic acid). (ii) -OH is the functional group present in `C_(2)H_(5)OH` (ethyl ALCOHOL). |
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| 1637. |
The Solubility of sodium nitrate at 50^@ C and 30^@ C is 114 g and 96 g respectively. Find the amount of salt that will be thrown out when a saturated solution of sodium nitrate containing 50 g of water is cooled from 50^@ C to 30^@ C? |
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Answer» SOLUTION : Amount of sodium nitrate dissolved in 100 g of water at `50^@ `C is 114 g `therefore `Amount of sodium nitrate dissolving in 50 g of water at -`50^@ `C is `(114 xx 50 )/( 100 ) =57 g` Similarlyamountof sodiumnitratedissolvingin 50gofwaterat `30 ^@ ` C is `= (96 xx 50 ) /( 100 ) = 48g ` AMOUNTOF sodiumnitratethrownwhen 50 gof wateris cooledfrom `50^@ `Cto `30^@ C` is |
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| 1638. |
What are magnetic field lines ? How is the direction of a magnetic field at a point determined ? |
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Answer» SOLUTION :The space surrounding a magnet in which magnetic force is exerted is called a magnetic filed. Magnetic FIELD lines are the lines that are drawn at every point indicating the direction in which a north pole would move if placed at that point. Thcy are determined by placing an imaginary hypothetical north pole at that point and finding the direction in which it would move due to the magnetic filed at that point of a COMPASS needle gets deflected when placed EAR a magnet due to the magnetic force exerted by the magnet on it. Some important properties of magnetic field lines are: The tangent drawn at any point on the field line indicates the dircction in which a north pole would move if placed at that point The relative strength of the ficld is proportional to the degree of closeness of Ihe lines. The mure elustered they are the stronger THC ficld in the region. The magnetic field lines never intersect This is bccause a pole can move only in zone direction and if the lincs interseet they wourld have to move in two direction aimultaneously which is npossible. |
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| 1639. |
What are photo decomposition reaction? |
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Answer» Solution :In this type of reaction ,the reactant is decomposed by APPLYING light. For example ,when silver BROMIDE is exposed to light ,it breaks down into silver METAL and bromine gas. `2AgBr_((s))overset("Light")to2Ag_((s))+Br_(2(G))` |
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| 1640. |
There are 3 unknown metals-A ,B and C,C displaces B from its oxide while with oxide of A, there is no reaction. Give the reactivity order of A, B and C. |
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Answer» SOLUTION :C displaces B from its OXIDE, therefore C is more reactive than B. There is no reaction when C is treated with oxide of A or C does not DISPLACE A from its oxide. So, A is more reactive than C. Thus, the reactivity orderis `B lt C lt A` |
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| 1641. |
What happens to a pin attached to the wire ? |
| Answer» Solution :DUE to heating, metal wire expands and the pin is displaced FORWARD. This INDICATE that heat flows through the wire and melts the wax but wire does not MELT. | |
| 1642. |
The sky appears dark to passengers flying at very high altitudes mainly because : |
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Answer» Scattering of LIGHT is not enough at such heights. |
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| 1643. |
What are normal elements? |
| Answer» Solution :ELEMENTS of group 1, 2 and 13 to 17 are callednormal elements. These elements have only the outermost shell incompletely FILLED. | |
| 1645. |
Write the structural formulae of all the isomers of hexane. |
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Answer» Solution :(a) `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-underset(H)underset(|)overset(H)overset(|)C-underset(H)underset(|)overset(H)overset(|)C-H` (B) `H-underset(H)underset(|)overset(H)overset(|)C-underset(CH_(3))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` (c )`H-underset(H)underset(|)overset(H)overset(|)C-underset(CH_(3))underset(|)overset(CH_(3))overset(|)C-underset(H)underset(|)overset(H)overset(|)C-underset(H)underset(|)overset(H)overset(|)C-H` (d)`H-underset(H)underset(|)overset(H)overset(|)C-underset(CH_(3))underset(|)overset(H)overset(|)C-underset(CH_(3))underset(|)overset(H)overset(|)C-underset(H)underset(|)overset(H)overset(|)C-H` (e ) `H-underset(H)underset(|)overset(H)overset(|)C-underset(H)underset(|)overset(H)overset(|)C-underset(CH_(3))underset(|)overset(H)overset(|)C-underset(H)underset(|)overset(H)overset(|)C-underset(H)underset(|)overset(H)overset(|)C-H` |
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| 1646. |
Which of the following is a non-polar molecule? |
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Answer» `NH_(3)` |
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| 1647. |
What is a covalent bond? What type of bond exists in (i) C Cl_(4) (ii) CaCl_(2)? |
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Answer» Solution :The chemical bonds formed between two atoms by the sharing of ELECTRONS between them is known as a covalent bond. The sharing of electrons between the two atoms takes place in such a way that both the atoms acquire stable electronic configuration of their nearest noble gas. `(i) C Cl_(4)` - Covalent bond, `(ii) CaCl_(2)` - IONIC bond |
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| 1648. |
The underground water is being overused. How can it be replenished ? |
| Answer» SOLUTION :By HARVESTING RAINWATER | |
| 1649. |
What are the conditions that promote corrosion ? |
| Answer» SOLUTION :Substances such as oxygen, CARBON dioxide, MOISTURE and acids PROMOTE CORROSION. | |
| 1650. |
Use your brain power, Classify the elements of the third period intometals and non - metals. |
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Answer» <P> Solution :Elements of third period are:`underset("Metals")ubrace(Na" " Mg" "AL)underset("Metalloid")overset(Si)darrunderset("Non-Metals")ubrace(P" " S" "Cl" "AR)` |
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