InterviewSolution
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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.
| 701. |
I have understood the reactions taking place in beakers 'A' and 'B'. But I am still confused why there is no change in beakers 'C', 'D' and 'E'? |
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Answer» SIMILARLY, no REPLACEMENT occurs in beaker 'D' and 'E'. |
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| 702. |
(i) Element X has two valence electrons in M-shell . (ii) In element Y, the electrons are distributed in the first three shells. It has eight electrons in M-shell. (iii) ElementZ has eight electrons in the penultimate shell that is M. Based on the information given in the above three statements, answer the following questions. (a) Give the electronic configuration of X. (b) Which element is stable among X, Y and Z and why ? (c) In which atom of an element is the number of electrons distributed in all four shells ? (d) What is the atomic number of Z in which the number of electrons in the first and the last shell are not the same ? What are the number of electrons and protons present in 'Y' ? |
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Answer» Solution :(a) Electronic configuration of X:2 , 8,2 (B) Element Y is STABLE due to the presence of 8 electrons (octet) in the valence SHELL. (c) In the element 'Z', the electrons are distributed in four shells because N-shell `(4^(th))` is the valence shell. (d) Since 8 electrons are present in penultimate shell that is M, 1 electron is present in N-shell because the number of electrons are not the same in K and N shell. Electronic configuration of 'Z' 2,8,8,1 Henceatomic number 'Z'=19. (e) Electronic configuration of Y=2,8,8. HenceZ=18 and the number of protons or electrons are 18. |
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| 703. |
Hydrogen sulphied from air is removed by passing air through |
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Answer» HYDROCARBON |
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| 704. |
Hydrogen chloride gas can be subjected to drying only with conc. H_2SO_4 but not with quick lime or phosphorus pentoxide. Explain |
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Answer» Solution :(i) Reaction of `P_2O_5` and CAO with HCL. (ii) Reactivity of the HQ with `H_2SO_4`, CaO, `P_2O_5`. (III) Reactions which are feasible. (iv) Products obtained. (V) Requisite for a drying AGENT. |
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| 705. |
Hydrogen acts as an oxidizing agent when it |
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Answer» reacts with HIGHLY ELECTROPOSITIVE metals |
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| 706. |
Hydrofiuoric acid cannot be stored in glass bottles like all other acids. Give reason. |
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Answer» SOLUTION :As is a silicate and HF REACTS with the silicates to FORM `SiF_4` and Huoride of METAL. `Na_2SiO_3+6HFrarr2NaF+SiF_4+3H_2O` `3SiF_43+H_2OrarrH_2SiO_3+2H_2SiF_6` |
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| 707. |
Hydrated copperr sulphate is not considered an efflorescent substance . Give reason. |
| Answer» Solution :Hydrated COPPER SULPHATE does not lost its WATER of CRYSTALLIZATION when exposed to air. | |
| 708. |
How will you identify whether a given solution is acidic in nature? |
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| 709. |
How was coal gas used earlier and how is it used today ? |
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| 711. |
How is sulphur dioxide produced? |
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| 712. |
How is Rutherford's theory in contradiction with the laws of electrodynamic ? |
| Answer» SOLUTION :A charged particles in MOTION LOSES energy and leads to COLLAPSE of ATOM | |
| 713. |
How is principle of counter currents is usefhl in Bachmann plant? |
| Answer» SOLUTION :MIXING up of chlorinc GAS with SLAKED LIME | |
| 714. |
How is oxygen gas prepared from potassium chlorate? What is the role of MnO_(2) in this process? |
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Answer» Solution :(i) Decomposition REACTION (II) CHANGE in reaction temperature |
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| 715. |
How is oxygen gas collected? |
| Answer» SOLUTION :DOWNWARD DISPLACEMENT of WATER. | |
| 716. |
How is natural gas stored ? |
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| 717. |
How is milk powder made from milk? Explain the principle involved. |
| Answer» Solution :Milk is heated under low pressure conditions. This decreases the boiling point of milk and thus the water present in the milk EVAPORATES. This concentrated milk is then sprayed in a HOT dry chamber where the EVAPORATION of the LEFTOVER water is instant and concentrated milk turns to milk POWDER. | |
| 718. |
How is methane prepared in the laboratory ? |
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Answer» Solution :(i) REACTANT (II) Conditions (III) Collection |
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| 719. |
How is hydrogen gas usedin metallurgy? Give an example. |
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Answer» Solution :Reducing AGENT e.g., `WO_(3) + 3H_(2) to W+3H_(2)O` |
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| 720. |
How is H_2S used as an analytical reagent? |
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Answer» SOLUTION :(1) Metal SULPHIDES (ii) PRECIPITATE (iii) Colour of precipitate |
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| 721. |
How is fractional crystallization process related to solubility curve ? |
| Answer» SOLUTION :The EXTENT of SOLUBILITY of SUBSTANCE in a given solvent. | |
| 722. |
How is coke formed ? Give two usesof coke. |
| Answer» Solution :Destructive distillation of COAL. Fuel, reducing AGENT, manufacture of GRAPHITE, `CaC_(2)`, water gas and producer gas . | |
| 723. |
how is coal gas obtained and how is it used ? |
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| 724. |
How is carbon monoxide produced? |
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| 725. |
How is bone charcoal prepared ? |
| Answer» SOLUTION :DESTRUCTIVE DISTILLATION of ANIMAL BONES. | |
| 726. |
How does sulphur dioxide affect human beings? |
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| 727. |
How does sky appear from the moon? |
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Answer» Solution :(i) Particles PRESENT in erath's atmoshphere which are responsible for scatterting fo LIGHT. (ii) Atmosphere in moon. (III) Reason for the specific colour (blue) of the sky when observed from the earth. (IV) Influence of atmosphere on the colour of the sky. |
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| 728. |
How does ozone layer protect us? |
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| 730. |
How does nitrogen occur in the combined state |
| Answer» SOLUTION :In the FORM of MINERALS, ORGANIC MATTER | |
| 731. |
How does liquefactionof a gas depend on critical temperature? |
| Answer» Solution :Liquefaction of a GAS by application of pressure is possible only at or below critical temperature.At low temperature the INTERMOLECULAR forces of ATTRACTIONS are considerably high. This makes the conversion of GASEOUS state to liquid state feasible on application of pressure. | |
| 733. |
How does fire extinguishers work? |
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| 734. |
How does dry powder type fire extinguisher work ? |
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Answer» Solution :A mixture of sand and sodium BICARBONATE can be USED to put off the burning material. The heat released from the burning material decomposes sodium bicarbonate and the carbon dioxide PRODUCED being heavier than air puts offs the flame. `2NaHCO_(3) to Na_(2)CO_(3)+H_(2)O+CO_(2)` |
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| 735. |
How do you account for the following ? (1) Nitric acid is colourless but on long standing it turns yellow. |
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Answer» SOLUTION :(i) CHANGES that take place innitric ACID on long standing. (ii)Effect of the product on nitric acid solution. (iii)Reactivety of HCl TOWARDS concentrated `H_2SO_4,P_2O_5` and quick lime. |
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| 736. |
How do we explain the survivla of aquatic animals in the deep sea, during winter in the cold region ? |
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Answer» Solution :(i) Comparison of densiites of water and ICE. (II) VARIATION of temperature at DIFFERENT layers in the SEA. (iii) Change in density of water with change in temperature. |
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| 737. |
How do chlorofluorocarbons cause air pollution? |
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Answer» Solution :(i) INERT nature of CFCs (ii) Effect of U.V. RAYS on CFCs (iii) Reactivity of CFCs (iv) ACTION of CFCs on ozone |
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| 738. |
How do catalytic converters reduce air pollution? |
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Answer» Solution :(i) Metal used in catalytic converter. (II) PROPERTY of the metal used in catalytic converter. (Places where catalytic converter finds APPLICATION. (iv) COMPOSITION of petroleum products used in automobiles. (v) Pollutants present in th automobile exhaust gases. (vi) Influence of the metal present in the catalytic converter on the exhaust gases. |
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| 739. |
How did the discovery of isotopes contradict Dalton's atomic theory ? |
| Answer» SOLUTION :LIKE ATOMS with unidentical MASS | |
| 740. |
How did Rutherford explain the stability of atom ? |
| Answer» SOLUTION :HIGH VELOCITY of ELECTRONS counterbalancing of FORCES of attraction | |
| 741. |
How did Neils Bohr explain the stability of atom? |
| Answer» SOLUTION :ENERGY of ELECTRON in an ORBIT. | |
| 742. |
How can you detect oxygen gas? |
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Answer» SOLUTION :(i) GLOWING splinter (II) Litmus (III) ALKALINE pyrogallol |
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| 743. |
How can we assess the quality of water? |
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| 744. |
How can the growing of plants control pollution? |
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Answer» SOLUTION :(i) Photsynthesis in plants (II) Gases TAKEN up during PHOTOSYNTHESIS |
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| 745. |
How can mercuric sulphide be prepared? |
| Answer» SOLUTION :`Hg+SrarrHgs` | |
| 746. |
How can hydrogen be prepared from natural gas ? |
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Answer» SOLUTION :(i) Constituents of NATURAL gas (ii) PRINCIPLE (iii) PROCESS |
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| 747. |
How are oxides of metals and non-metals formed? |
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| 748. |
How are natural fibres obtained? |
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| 749. |
How are carrier wave produced? |
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