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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.
| 1801. |
Which of the following ca nbe utilized to produce electricity ? |
| Answer» Answer :C | |
| 1802. |
Write the main aim of classifying elements. Name the basic property of elements used in thedevelopment of Modern Periodic Table. State the Modern Periodic Law. On which side (part) of the Modern Periodic Table do you find metals, metalloids and non-metals? |
| Answer» SOLUTION :Elements are classified for systematic and simplified study of elements and their compounds. Thebasic PROPERTY of elements used in the Modern PERIODIC Table is the atomic number of the elements. Modern Periodic Law states that “the properties of elements are a periodic function of their atomic number.” METALS are found on the left side and centre of the Modern Periodic Table. Non-metals are found on the right side of the Modern Periodic Table. Metalloids are found in a zig-zag manner between the metals and the non-metals. | |
| 1803. |
Which is a stronger acid, with pH =5 or with pH=2? |
| Answer» SOLUTION :PH=2 (LOWER the pH, STRONGER the ACID) | |
| 1804. |
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 involved and also write a test to detect the gas formed. |
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Answer» SOLUTION :When zinc reacts with dilute solution of strong acid, it forms salt and hydrogen gas is evolved. `Zn + 2HCl RARR ZnCl_(2) + H_(2)` When a burning splinter is brougth near the MOUTH of the test tube, the gas BURNS with a pop sound. |
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| 1805. |
Three acidic solutions A, B and C have pH=0,3 and 5 respectively (i) Which solution has highest concentration of H^+ ions ? (ii) Which solution has the lowest concentratoin of H^+ ions ? |
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Answer» Solution :Solution A has the HIGHEST concentration of `H^+` IONS (II) Solution C has the LOWEST concentration of `H^+` ions. |
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| 1806. |
Which of the following pasirs give displacement reactions? (i) NaCl solution and copper metal (ii) MgCl_(2) solution and aluminium metal (iii) FeSO_(4) solution and silver metal (iv) AgNO_(3) solution and copper solution |
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Answer» NACL solutioin and copper METAL. |
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| 1809. |
What do you mean by emision and absorption spectra ? |
| Answer» Solution :When the ENERGY EMITTED by an atom due to tne de-exciation of electrons is observed through a spectroscope ,it appears consisting of BRIGHT lines on a dark BACKGROUND ,this is emission spectrum.The spectrum formed due to the absorption of energy during the ecitaion of elctrons CONSISTS of dark lines on a bright background , this is called absosrption spectrum. | |
| 1810. |
Where would you locate the element with electronic configuration 2,8 in the Modern Periodic tabel ? |
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Answer» GROUP 8 |
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| 1811. |
What is the chemical name of the soap prepared from castor oil ? |
| Answer» Solution :CASTOR oil CONTAINS GLYCERYL oleate. So, the soap PREPARED from castor oil sodium oleate. | |
| 1812. |
Write the reactions between ethanol and conc. H_2 SO_4 at 170^@C. |
| Answer» Solution :`UNDERSET("ethanol")(C_2H_5OH) OVERSET(conc. H_2SO_4)(to) underset("ETHENE")(C_2H_4) + underset("WATER")(H_2O)` | |
| 1814. |
The stable isotope of …………….is used as the standard for measuring the relative atomic mass of an element. |
| Answer» SOLUTION :CARBON C- 12 | |
| 1816. |
What happens when zinc granules are trated with dilute solutions of H_(2)SO_(4), HNO_(3), NaCl and NaOH ? Also writethe chemical equation. |
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Answer» Solution :(i) With dilute `H_(2)SO_(4):H_(2)` gas is evolved. `Zn+H_(2)SO_(4)rarr ZnSO_(4)+H_(2)UARR` (ii) With dilute `HNO_(3):H_(2)` gas is evolved. `Zn+2HNO_(3)rarrZn(NO_(3))_(2)+5H_(2)O+H_(2)uarr` (III) With dilute NaCl : No Chemical REACTION takes place . (iv) With dilute NaOH : Sodium Zincate is formed and `H_(2)` gas is evolved . `Zn+2NaOHrarr Na_(3)ZnO_(2)+H_(2)uarr` |
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| 1817. |
Which of these metals cannot be obtained by reduction using C as reducing agent ? |
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Answer» copper |
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| 1818. |
The ______ tableis tabulararrangement of elements in rows and columns. |
| Answer» SOLUTION :MODERN PERIODIC | |
| 1819. |
What is milk of magnesia ? Is it a strong or mild base ? |
| Answer» SOLUTION :Milk of magnesia is `MG(OH)_2`It is a MILD base. | |
| 1820. |
Whatare the metals used in manufacture ofscience equipment ? |
| Answer» SOLUTION :ALUMINIUM, MAGNESIUM | |
| 1821. |
Which pair of elements has similar properties? |
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Answer» 13,31 Element with `z=13to2,8,3` Element WIT `z=31to2,8,18,3` |
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| 1822. |
Write the chemical equation for the following : Hydrogen sulphide reacts with sulphur dioxide to form sulphur and water |
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Answer» SOLUTION :`4H_(2)S+2SO_(2)to6S+4H_(2)O` The NEED of balancing the equation is that an equation should be written as per the LAW of conservation of mass. It states that the number of ATOMS of each element before and after the REACTION should remain same. |
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| 1823. |
What is short circuit ? State one condition that leads to it . Name the device in the household that acts as a safety measure for it. |
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Answer» Solution :When live wire and neutral wire come in DIRECT contact, a heavy CURRENT in the circuit is called SHORT circuiting. FACTOR : Insulation of wire is damaged. Safety device :Electric FUSE. |
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| 1824. |
Write the balanced chemical equations for the following reactions : Copper sulphate on treatment with potassium iodide precipitates cuprous iodide (Cu_(2)I_(2)) liberates I_(2) gas ans also forms potassium sulphuric. |
| Answer» SOLUTION :`2CuCO_(4)+4KI to Cu_(2)I_(2)+I_(2)+2K_(2)SO_(4)` | |
| 1825. |
What is meant by a skeletal chemical equation ? Using a suitable example differentiate between a skeletal and a balanced chemical equation. |
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Answer» SOLUTION :Skeletal equation - It is an unbalanced CHEMICAL equation, where the number of ATOMS of reactants and products unequal. e.g. `H_(2)+Cl_(2)toHCl`. BALANCED equation - It is a chemical equation where the number of atoms of reactants and products equal. It also indicates the conditions of the reaction and the states of the reactants and products formed. e.g. : `H_(2)(g)+Cl_(2)(g)to2HCl(g)`. |
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| 1826. |
What is the difference between displacement and double displacement reactions ? Write equations for these reactions. |
Answer» SOLUTION :
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| 1827. |
Which of the following correctly represents 360 g of water? (i) 2 moles of water (ii) 20 moles of water (iii) 6.023xx10^(23) molecules of water (iv) 1.2044xx10^(23) molecules of water |
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Answer» (i) only Mass of 1 mole of water = 18 g `therefore " mass of 2 moles of water"` `=18xx2=36g` (ii) 20 moles of water Mass of 1 mole of water = 18 g `therefore"Mass of 20 moles of water"` `=18xx20=360g` (iii) `6.023xx10^(23)" MOLECULES of water "=1` mole = 18 g (iv) `1.2044xx10^(25)" molecular of water "6.023xx10^(23)" molecules of water "="1 mole"` `therefore 1.2044xx10^(25)" molecules"` `=(1)/(6.023xx10^(23))xx1.2044xx10^(25)` = 20 moles `therefore"Mass of 20 moles "=20xx18=360g` So (d) is correct. |
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| 1828. |
Why are detergents better cleansing agents than soaps? Explain. |
| Answer» Solution :DETERGENTS are GENERALLY ammonium or sulphonate salts of long-chain carboxylic acids. The charged ends of these compounds do not form insoluble precipitates with the CALCIUM and magnesium ions in hard water. Thus, they remain effective in hard water. Soaps are sodium or potassium salts of long-chain FATTY acids which REACT with calcium and magnesium ions in hard water and form a scum (a insoluble precipitate of soap). | |
| 1829. |
Which of the following is (are) an endothermic process(es) ? (i) Dilution of sulphuric acid(ii) Sublimation of dry ice (iii) Condensation of water vapours(iv) Evaporationof water |
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Answer» (i) and (iii) |
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| 1830. |
What were the limitations of Newlands' law of octaves ? |
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Answer» Solution :( 1 ) Newlands law of octaves was applicable only to lighter elements having atomic masses upto 40 u. (2) The law of octaves was applicable only upto calcium, because after calcium every eighth element did not possess properties similar to that of the first element. (3) Newlands assumed that only 56 elements existed in nature and no new elements would be discovered in the future. But, later on, several new clements were discovered whose properties did not fit into the law of octaves. ( 4 ) In order to fit elements into his table, Newlands adjusted TWO elements in the same slot, but also put some unlike elements under the same column. For example, cobalt (Co) and nickel (Ni) are placed in the same slot and these are placed in the same column as fluorine, chlorine and bromine which have very DIFFERENT properties thanthese elements. Iron, which RESEMBLES cobalt and nickel in properties, has been placed far away from these elements. |
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| 1831. |
Write the chemical equation for reaction when lead nitrate and potassium iodied are mixed. |
| Answer» SOLUTION :`UNDERSET("Lead nitrate")(PB(NO_(3))_(2))underset("Potassium iodide")(+2KI)RARR underset("Potassium nitrate")(2KNO_(3)+)underset("Lead iodide1)(PbI_(2))` | |
| 1832. |
The temperature at which a solid changes into liquid is called |
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Answer» melting POINT of the solid |
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| 1833. |
Write the molecular formula, electron dot structure and graphic structural formula of ethene |
| Answer» SOLUTION :`(i) C_2H_4 (II) H:C::C:H (III) H - undersetoverset(|)(H)(C) = undersetoverset(|)(H)(C) - H` | |
| 1834. |
When a mixture of iron filings and sulphur is treated with dilute hydrochloric acid, |
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Answer» FERRIC CHLORIDE is FORMED |
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| 1835. |
You are provided with magnesium ribbon and sulphur powder. Explain with the help of an activity that metal oxides are basic and non metal oxide are acidic in nature. |
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Answer» Solution :To test the nature of oxides FORMED by METALS and non metals. Materials required sulphur powder, MG ribbon, water, blue litmus paper, red litmus paper Procedure: Take a magnesium ribbon with a pair of tongs and burn it in flame in the presence of air. Collect the product formed and dissolve it in ward water. Add red litmus paper into it. Observe the change in colour and decide the nature of the oxide formed. Burn sulphur in a deflagrating spoon in the presence of air and disolve the oxide formed in water. Dip blue litmus paper into the solution and observe the change in the colour and decide the nature of the oxide formed. Observation: The oxide formed by meal turns red litmus blue whereas oxide of non metal turns blue litmus red. Chemical reactions: `2Mg(s)+O_(2)(g)OVERSET("burning")(to)2MgO(g)` `S(s)+O_(2)(g)toSO_(2)(g)` `SO_(2)(g)+H_(2)O(1)toH_(2)SO_(3)(aq)` Conclusion: Most of the METALLIC oxides are basic in nature whereas most the non metallic oxides are acidic in nature. |
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| 1836. |
When an element of group 14 is doped with a pentavalent element which kind of semi conductors are formed |
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Answer» <P>p type |
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| 1837. |
When a copper wire was left in silver nitrate solution for sometime, it was observed that thesolution turned bluish green. (i) Explain the observation . (ii) Write the balanced chemical equation to represent thechange taking place. |
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Answer» Solution :(i) COPPER is more reactive than silver. Hence, when copper wire is dipped in silver nitrate solution, it DISPLACES silver from `AgNO_(3)` solution formingcopper nitrate which is blush green in COLOUR. (II) `Cu+2AgNO_(3)rarrunderset(("Copper (II)nitrate bluish green"))(Cu(O_(3))_(2))+underset(("Silver"))(2Ag)` |
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| 1838. |
What is homologous series of carbon compounds ? Write the molecular formula of two consecutive members of homologous series of aldehydes. State which part of these compounds determines their (i) physical and (ii) chemical properties. |
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Answer» Solution :A homologous series is a series of ORGANIC compounds which belong to the same family (i.e. possess same functional group) and show similar chemical properties. The members of this series are called homologous and differ from each other by the number of `CH_(2)` units in the main CARBON chain Molecular FORMULA of two CONSECUTIVE members of homologous series of aldehydes is `CH_(3) -CHO and CH_(3)-CH_(2)-CHO.` In `CH_(3) - CHO` compound -CHO PART and in `CH_(3) -CH_(2) CHO, -CH_(2) -CHO` Part will deter mine their physical and chemical properties. |
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| 1839. |
Which amongst the following element can from amphoteric oxide ? |
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Answer» Mg |
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| 1840. |
There are three elements E, F, G with atomicnumbers 19, 8 and 17 respectively.Give the molecular formula of the compoundformed between E and G and state the typeof chemical bond in this compound. |
| Answer» SOLUTION :EG, ELECTROVALENT BOND | |
| 1841. |
Which of the following subshells is not possible in an atom ? |
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Answer» 2p |
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| 1842. |
Write the formulation for the functional groups of alcohols and carboxylic acids. |
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Answer» SOLUTION :Alcohols : - OH CARBOXYLIC ACIDS : `- UNDERSET(OH)underset(|)(C ) = O` or -COOH |
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| 1843. |
What change will you observe if you test soap with litmus paper (red or blue) ? |
| Answer» SOLUTION :Soap is basic (alkaline) in nature, it TURNS RED LITMUS paper BLUE, while, it does not have any effect on blue litmus paper. | |
| 1844. |
Translate the following statements into chemical equations and then balance them : Hydrogen gas combines with nitrogen to form ammonia. |
| Answer» SOLUTION :`{:(" "H_(2)(g)+N_(2)(g)toNH_(3)(g)"(Unbalanced EQUATION)"),(" 3"H_(2)(g)+N_(2)(g)to2NH_(3)(g)"(BALANCED equation)"):}` | |
| 1845. |
Three elements B, Si and Ge are |
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Answer» Metals |
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| 1846. |
You are given a hammer, a battery , a bulb, wires and a switch. How could you use them to distinguish between samples of metals and non metals. (b) Assess the usefulness of these tests in distinguishing between metals and non metals. |
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Answer» Solution :(i) We use the hammer to break the sample. If the sample breaks, this means that it it BRITTLE and hence it is a non metal. On the other hand if the sample flattens to form a sheet, this means than the sample is malleable and hence is metal. (ii) We set up the electric circuit and place the sample is between CLIPS A and B and put the switch on. IF the BULB glows, the sample is a good conductor of electricity and hence it must be a metal . If on the other hand, the bulb does not glow, the sample is a poor conductor of electricity and hence it must be a non metal. (ii)Because ofmalleability of iron and many other metals, we can cast them into sheets, which can be used for various purposes . For example, iron sheets are used for roofing and for making trunks, boxes etc. Metals are good conductors of electricity. It is because of this property that metal wires made up of copper and aluminium are used for carrying electricity. These tests of distinguishing metals and non metals are widely applicable in industries and its validity has been SCIENTIFICALLY proved. |
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| 1847. |
Which of the following is a property of an acid. |
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Answer» Slippery |
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| 1848. |
Which metals do not react with cold water and steam? |
| Answer» SOLUTION :Pb, Cu, Ag and Au do not REACT with COLD water and STEAM. | |
| 1849. |
Which allotropic form of carbon has a two dimensional sheet like structure? |
| Answer» SOLUTION :Graphite | |
| 1850. |
Why are the electron affinities of alkaline earth metals positive? M_((g))+e^(-) to M^(-)_((g)) DeltaH =+ ("Electron affinity") |
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Answer» SOLUTION :All the ELECTRONS present in alkaline earth metals are paired. Therefore to add one extre electron to these ATOMS, work has to be done against the force of repulsion. Hence, electron AFFINITY of an alkaline earth metal is a positive. |
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