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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.
| 2001. |
Extremely electropositve metals are present in ________and ________groups |
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| 2002. |
Express the boiling point of water in a. the Celsium b. the Kelvin scales. |
| Answer» SOLUTION :a. `100^(@)C` b. 373 K | |
| 2003. |
Among the following, identify the substance in which molecules posses viratory, rotatory and translatory motions in all directions except in one direction. |
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Answer» bromine |
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| 2004. |
Explain with examples (a) Atomic number Mass number Isotopes |
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Answer» Solution :(i) Atomic number : The atomic number of an element is the total number of protons present in the ATOM of that element. For Ex : NITROGEN has 7 protons in its atom. Thus, the atomic number of Nitrogen is 7. (II)Mass number : The mass number of an element is the sum of the number of protons and neutrons present in the atom of that element. For Ex : The atom of Boron has 5 protons and 6 neutrons. So, the mass number of baron is `5+6=11` (iii) Isotopes: These are ATOMS of the same element having the same atomic number, but different mass numbers. For example, Chlorine has two isotopes with atomic number 17 but mass number 35 and 37 represented by `{:(35,37),(Cl,Cl),(17,17):}` (iv) Isobars : These are atoms having the same number, but different atomic number i.e., Isobar are atoms of different elements having the same mass number. For Ex : Ne has atomic number 10 and Sodium has atomic number. 11 but both of them have mass number. 22 represented by,`._(10)^(22)Ne, ._(11)^(22)Na` Give any two uses of Isotopes : Two uses of Isotopes : One isotope of URANIUM is used as fuel in nuclear reactors One isotope of Cobalt is used in the treatment of cancer. |
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| 2005. |
Explain with equations the reaction of sulphur with metals and non-metals |
| Answer» SOLUTION :N/A | |
| 2006. |
Explain why the addition of an elctron to a neutral atom is associated with release of energy |
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Answer» Solution :(i) type of foces presentbetween an added ELECTRON and NEUTRAL atom (ii) the type of FORCES responsible for addition of ELECTRONS (iii) ENERGY changes involved when electrons are added |
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| 2007. |
Among all the groups the maximum number of elements is found in IIIB group |
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| 2008. |
Explain why particles of a colloidal solution do not settle down when left undisturbed, while in the case of a suspension they do? |
| Answer» Solution :In a colloidal solution, the particle size is smaller as compared to particle size in a SUSPENSION. The effect of gravity on these PARTICLES is LESS than in a suspension. THEREFORE, the particles in a suspension settle under the INFLUENCE of gravity while they remain dispersed in a colloidal solution. | |
| 2009. |
Ammonium chloride and camphor are volatile substances. The mixture of these can be separated by _____ . |
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Answer» sublimation |
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| 2010. |
Explain why N_2O supports combustion mor vigorously than air. |
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Answer» Solution :(i) requisite to support COMBUSTION (ii) products FORMED on decomposition of `N_2O` (iii) volume of one of the product in air which SUPPORTS combustion (iv) comparison of volumes of the COMPONENT in air and product of `N_2O` which supports combustion |
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| 2011. |
Explain why a blackened plantinum strip when placed the radius of curvature red hot, only when the cathode taken has concave shape. |
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Answer» Solution :(i) FACTORS responsible for the strip to TURN red hot (ii) The PATH in which the ELECTRONS travel from concave CATHODE. |
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| 2012. |
alphaParticels are |
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Answer» NEGATIVELY CHARGED PARTICLES |
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| 2013. |
Explain water of erystallisation. |
| Answer» Solution :MANY salts are found as crystals with water MOLECULES they contain: These water molecules are known as water of crystallisation. Salts that contain water of crystallisation are called hydrated salts. The number of molecules of water hydrated to a salt is indicated after the DOT in cits chemical formula. For example, copper sulphate crystal have five molecules of water for each molecule of copper sulphate. It is written as `CuSO4.5H2O` and named as copper sulphate pentahydrate. This water of crystallisation makes the copper sulphate blue When it is HEATED, it loses its water molecules and BECOMES white. Salts that do not entitats water of crystallisation is called anhydrous salt. | |
| 2015. |
Explain Tyndall effect with the help of a figure. |
Answer» SOLUTION :Take copper sulphate solution (true solution) in one beaker and colloidal solution in the other beaker. Place the beakers in dark room and allow the beam of light to pass through the beakers. The beam of light after passing through the colloidal solution GETS scattered and becomes visible. This is CALLED the TYNDALL effect.  The effect is not SEEN in true solution. |
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| 2016. |
alpha-Particles are ……………. Charged. |
| Answer» SOLUTION :POSITIVELY | |
| 2017. |
Explain Tyndall effect and Brownian movement with suitable diagram. |
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Answer» Solution :A. Tyndall Effect: When a strong beam of light is focused on a colloidal solution the path of the beam becomes visible. This phenomenon is called as Tyndall effect. The illuminated path is called Tyndall cone. This phenomenon is due to scattering of light by colloidal particles.  B. Brownian movement: It is a kinetic property. When colloidal solution are viewed under powerful MICROSCOPE, it can be seen that colloidal particles are moving CONSTANTLY and RAPIDLY in zig-zag directions. The Brownian movement of ARTICLES is due to the unbalanced bombardment of the particle by the molecules of dispersion medium. 
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| 2018. |
Along a period atomic volume of the elements gradually increases from left to right due to an incerase in the number of valence electrons |
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| 2019. |
Explain the uniqueness of Hydrogen. |
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Answer» Solution :Hydrogen is the lightest, smallest and first element of the PERIODIC table. Its electronic configuration `(1 s^(-1))` is the simplest of all the elements. It occupies a unique position in the periodic table. It behaves like ALKALI metals as well as halogens in its properties. In the periodic table, it is PLACED at the top of the alkali metals. (i) hydrogen can lose its only electron to form a hydrogen ion (H+) like alkali metals. (ii) It can ALSO gain one electron to form the hydride ion (H-) like halogens. (iii) Alkali metals are SOLIDS while hydrogen is a gas. |
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| 2020. |
Explain the types of dyes based on their method of application. |
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Answer» Solution :Dyes are classified in TWO ways, one, based on the method of application and other on their PARENT structure. Based on method of application Acid dyes: These are acidic in nature and used for dyeing animal fibres and synthetic fibres. These can be used for protein fibre such as wool and silk. E.g. Picric acid, Naphthol yellow-s Basic dyes: These are basic dyes containing basic group `(-NH_(2), -NHR, -NR_(2))`. They are used for dyeing animal fibres and plant fibres. Mordant dyes or Indirect dyes: These dyes have a poor affinity for cotton fabrics and hence do not dye directly. They require pretreatment of the fibre with a mordant. Mordant (latin : mordere = to BIT) is substance which can be fixed to the fibre and then can be combined with the dye to form aninsoluble complex called lake. Aluminium, chromium, and iron salts are widely used as mordants. E.g. alizarin. Direct dyes: They have high affinity for cotton, RAYON and other cellulose fibre. So they are applied directly as they fix firmly on the fabric. E.g. Congo red Vat dyes: It can be used only on cotton and, not on silk and wool. This dyeing is a continuous process and it CARRIED out in a large vessel called vat. So it is called as vat dye. E.g. Indigo |
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| 2022. |
Explain the three states of matter. |
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Answer» Solution :Matter exists in three DIFFERENT states: Solid, LIQUID and gas. 1.Solid states: (1) SOLIDS have definite shape, distinct boundaries and fixed volumes. 2. Solids may break under force but it is difficult to change their shape. So they are rigid. Exception: Sponge can be pressed because it has minute spores in it. When we press the sponge the air present in the pores is released. On removing presure it regains its shape. 2.Liquid state: 1. Liquids have two definite shape, Hence they take the shape of the container. 2. Liquids have definite volume. 3.Liquid can flow, its not ridig, 4. Solid and liquid matter can diffuse in lilquid. Some gases can also diffuse in liquid. 5. The rate of diffusion of liquid is more than that of solid. This is because the particles in liquid state can move freely. 6. There is neglilgible decrease in volume of the liquid when pressure is applied. 3.Gaseous state:1. They do not have definite shape nor definite volume. 2. Large quantity of gas can be diffuses very fast. 4.The particles of gas move RANDOMLY with very high speed and spread throughout the vessel inwhich it is kept. 5. The particles of gas strike on the walls of two container and produce pressure. |
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| 2023. |
Explain the structure of an electrolytic cell. |
Answer» SOLUTION : • It is an electrochemical cell which converts electrical energy into chemical energyi.e. in electrolytic cells, electricity is used to bring about chemical reactions. • Here, both anode and cathode are in contact with same electrolyte and and thus the half-cells are not separated. As seen in GALVANIC cells, electrolytic cell also involves redox reaction. We get electricity from galvanic cells. But electrolytic cells USE electricity. • In electrolytic cells, when electricity is passed to the electrolyte, it dissociates into its CONSTITUENT ions. These ions undergo redox reaction forming the respective elements. This PHENOMENON is called Electrolysis. So electrolysis is a process by which an electrolyte is decomposed into its constituent elements by passing electricity through its aqueous solution or fused (molten) state. |
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| 2024. |
Explain the separation techniques involved in the separations of constituents in gunpowder. What types of reactions are involved in the explosion of gunpowder ? |
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Answer» SOLUTION :(i) components of GUNPOWDER (II) solubility of the components in water and `CS_2` (iii) products OBTAINED on oxidation of CONSTITUENTS of gunpowder (iv) consitituent of gun poweracting as oxygen provider. |
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| 2025. |
Explain the role of pH in our digestive system. |
| Answer» Solution :The pH of saliva is USUALLY between 6.5-75. pH of stomach fluid is approximately 2.0. This is because it produces hydrochloric acid which HELPS in the digestion of food without harming the stomach. pH in the SMALL and large intestine ranges from 4.0 7.0. | |
| 2026. |
Alloys bear the characteristics of both metals and nonmetals. |
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| 2027. |
Alloys are regarded as solutions. |
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| 2028. |
Explain the role of natural gas in the preparation of ammoniun fertilisers . |
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Answer» SOLUTION :(i) raw materials for PREPARATION ammonia. (ii) reaction of chief CONSTITUENT of natural GAS to give the raw material required. (iii) Haber s process . (iv) role ofproduct ofI-Iaber s process in manufac turing ammonium FERTILISERS |
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| 2029. |
All the students of class 9 were performing experiments to study the types of solutions in the science laboratory. Vikalp took some water in a beaker and heated it slowly with the help of a burner.He starded adding postassium nitrate to the hot water with a spoon and stirred it with a glass rodcontinuously, so that potassium nitrate goes on dissolving in water. Vikalp took the temperature of water up to 40^(@)C, and then keeping the temperature constant, went on adding more and more of potassium nitrate to water, till no more potassium nitrate dissolved in it and some potassium nitrate is also left undissolved at the bottom of beaker. The contents of the beaker are now filtered through a filter paper arranged in a funnel. A clear solution is obtained in the form of a filtrate (a) Depending upon the amount of solute present, the solution can be classified into two groups. Name these two groups of solution (b) What type of potassium nitrate solution prepared by Vikalp at 40^(@)C ? Define the type of solution prepared by Vikalp (c) What will happen if the potassium nitrate solution prepaerd by Vikalp at 40^(@)C ? is heated further (say to 60^(@)C) ? Give reason for your answer (d) What will happen if the potassium nitrate solution prepared by Vikalp at 40^(@)C is allowed to cool (say to 20^(@)C) ? Give reason for your answer (e) Which term/phrase can be used to convey that a maximum of 106 grams of potassium nitrate can be dissolved in 100 grams of water at a temperature of 60^(@)C ? (f) What values are displayed by Vikalp in this episode ? |
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Answer» Solution :(a) (i) Saturated solutions, and (II) Unsaturated solutions (b) (i) Vikap has prepared a saturated solution of POTASSIUM NITRATE at `40^(@)C` (ii) A solution in which no more solute (here potassium nitrate) can be dissolved at that temperature, is called a saturated solution (c) If the saturated solution of potassium nitrate at `40^(@)C` is heated further to a higher temperature, then it will become an unsaturated solution (and more of potassium nitrate can then be dissolved in it). This is because the solubility of potassium nitrate in water increases on heating (or raising the temperature) (d) If the saturated solution potassium nitrate at `40^(@)C` is allowed to COOL, then some of the DISSOLVE potassium nitrate from the solution will separate out as a solid and settle down at the bottom of the beaker. This is because the solubility of potassium nitrate in water decreases on cooling (or lowering the temperature) (e) The solubility of potassium nitrate in water is 106g at `60^(@)C` (f) The values displayed by Vikalp in this episode are (i) Awareness of saturated and saturated solutions (ii) Knowledge of effect of heating and cooling on saturated solutions, and (iii) Applications of knowledge in solving problems. |
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| 2030. |
Explain the role of lime and washing soda for the removal of permanent hardness of water. |
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Answer» Solution :(i) chemical COMPOSITION of lime and washing soda (ii) reasons for the PERMANENT hardness of water (iii) REACTION between components of permanent hard water and lime (iv) reaction between components of permanent hard water and washing soda (V) SOLUBILITY of the products obtained in the above reactions (vi) relation between the solubility of the products and hardness of water |
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| 2031. |
Explain the raction of ammonia with chlorine ? |
| Answer» SOLUTION :N/A | |
| 2032. |
All the material substances contain small particles. |
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| 2033. |
Explain the postulates of Bohr's atomic model. |
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Answer» Solution :The main postulates of Neil.s Bohr are as follows. 1.In atoms, electrons REVOLVE AROUND the nucleus in special ORBITS called discrete orbits or shells or energy levels. 2. While the electrons revolve, they do not radiate energy. While the electrons revolve, they do not radiate energy . 3. The circular orbits are numbered as 1 , 2 , 3 , 4 , or designated as K, L , M , N shells . These numbers are referred as principal quantum numbers (n) . 4. K shell (n=1) is closer to the nucleus and is associated with lowest energy . L , M, N are the next higher energy levels . As the distance from the nucleus increases, the energy of the shells also increase. 5.The energy of each orbit or shell is a fixed quantity . 6 . As the distance from the nucleus increases, the size of the orbits also increases. 7. The maximum number of electrons that can be accommodated in an energy is `2n^(2)` (n= quantum number of its orbit). 8.When an ELECTRON absorbs energy, it jumps from lower energy level to higher energy level. 9. When an electron returns from higher energy level to lower energy level , it gives off energy. 
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| 2034. |
How do you define interconversion of states of matter? |
| Answer» SOLUTION :The inertmolecular force of attraction is maximum in the solid STATE and minimum in the gaseous state. Similarly, the KINETIC energy of the molecules is minimum in the solid state and maximum in the gaseous state. The CHANGE of state can be brought about by either CHANGING the temperature or pressure. | |
| 2036. |
Draw the structure of ammonia molecule. |
Answer» Solution : To attain the electronic configuration of the nearest noble gas, nitrogen needs THREE electrons and hydrogen needs ONE electron. When a MOLECULE of ammonia is to be formed, one ATOM of nitrogen shares three electron PAIRS, one with each of the three atoms of hydrogen. Formation of an ammonia molecule 
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| 2037. |
All samplesof water contain hydrogenand oxygen in the mass ratio1:8. This is in agreement with the law of |
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Answer» CONSERVATION of mass |
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| 2038. |
Explain the following: Potassium is stored under kerosene oil. |
| Answer» SOLUTION :POTASSIUM reacts with atmospheric oxygen and MOISTURE. | |
| 2039. |
Explain the following giving examples : (a) Saturated solution (b) Pure substance ( c) Colloid (d) Suspension |
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Answer» Solution :(a) Saturated solution : A solution in which no more solute can be dissolved at a given temperature is called a saturated solution. Example : 32 G of potassium nitrate dissolved in 100 g of water at 293 K forms a saturated solution. (b) PURE substance : A substance which consists of a single type of particles is called a pure substance. A pure substance has a definite boiling point and melting point. Example : Pure water. ( C) Colloid : A colloid is a solution in which the size of the particles are small (bigger than TRUE solution) and cannot be seen with an unaided eye. The particles of colloid scatter a beam of light passing through the solution. Example : Fog, smoke, blood, etc. (d) SUSPENSION : It is a heterogeneous mixture. The solute particles are big enough and can be seen with an unaided eye. The particles of suspension settle down when left undisturbed. Example : Mud particles in water. |
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| 2040. |
All samples of carbon dioxide containcarbon and oxygen in the mass ratio of 3:8 This is in agreement with the law of .(a). conservation of mass (b). constant proportion(c). multiple proportions(d). gaseous volumes |
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Answer» conservation of mass |
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| 2041. |
Explain the following giving examples. (a) Saturated solution (b) pure substance (c ) colloid (d) suspension |
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Answer» Solution :(a) Solution in which no more solute can be dissolved at a particular temperature is known as SATURATED solution. For example in AQUEOUS solution of sugar no more sugar can be dissolved at room temperature. (b) A PURE SUBSTANCE is a substance consisting of a single type of particles i.e., all constituent particles of the substance have the same chemical properties. For example water, sugar, salt etc. (c ) A colloid is a heterogeneous mixture whose particles are not as small as solution but they are so small that cannot be seen by naked eye. When a beam of light is passed through a colloid then the path of the light becomes visible. For example milk, smoke etc. (d) A suspension is a heterogeneous mixture in which solids are dispersed in liquids. The solute particles in suspension do not dissolve but remain suspended throughout the medium. For example PAINTS, Muddy water chalk water mixtures etc. |
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| 2042. |
Explain the following giving examples (a) Saturated solution (b) Pure substance (c) Colloid (d) Suspension |
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Answer» Solution :(a) Saturated solution :- Solution in which no more solute can be dissolved at a particular temperature is known as saturated solution. For example in AQUEOUS solution of sugar no more sugar can be dissolved at room temperature. (b) Pure Substance :- Any substance is said to be pure if and only if it is MADE up of SINGLE type of particles means all the particles of that substance should be of same chemical NATURE. For example water, sugar, salt etc. (c) Colloid :- A colloid is a heterogeneous mixture whose particles are not as small as solution but they are so small that cannot be seen by naked eye. When a beam of light is passed through a colloid, then the path of the light becomes visible. For example milk, smoke etc. (d) Suspensio :- A suspension is a heterogeneous mixture in which solids are dispersed in liquids. The solute particles in suspension do not dissolve but remain suspended throughout the medium. For example paints, MUDDY water, chalk water mixtures etc. |
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| 2043. |
"All pure substances are homogeneous. But, all homogeneous substances are not pure". Justify |
| Answer» Solution :A PURE substance is the one which is made up of same kind ofmolecules. So, it is homogeneous in NATURE. A mixture which has uniform DISTRIBUTION of DIFFERENT kinds of molecules is alsohomogeneous but it is not pure as it contain TWO or more kind of molecules. | |
| 2044. |
Explain the following: Anhydrous iron (III) chloride turns to a solution when exposed to air. |
| Answer» SOLUTION :It is a DELIQUESCENT substance. It absorbs MOISTURE from the AIR and gets dissolved in it. | |
| 2045. |
Explain the following: A solution of CuSO_(4) cannot be stored in a pot made of iron. |
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Answer» Solution :IRON is more reactive than COPPER, so it displaces copper from its salts. `CuSO_(4)+FetoFeSO_(4)+CU` |
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| 2046. |
All elements having valency 2 are called divalent . |
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| 2047. |
Explain the factors, which will affect the rate of evaporation, taking examples from our daily life experiences. |
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Answer» Solution :(a) Temperature: Warmer the EVAPORATION surface, the higher the rate of evaporation. In PONDS, lakes and RIVERS, the rate of evaporation is more in sunny days. (b) Surface area: The evaporation INCREASE, with the increase of surface area. Eg: The waater kept in a saucer evaporates faster than the water kept in a glass. (c ) Humidity: The amount of water vapour is high during rainy season. The air can hold little water, So it slows down the evaporation. So we sweat and perspire. (d) Wind: The evaporation is slow at LOW wind. Evaporation is faster at high wind. The particles of water move away, along with the particles of air at high wind. so the wet clothes dry faster on a windly day. |
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| 2048. |
Explain the energy changes inovoled in the formation of f and O^(2) form their respecitive atoms |
| Answer» Solution :Though `F^(-)` and `O^(-2)` are ISOELECTRONIC speices the formation of `F^(-)` is exothemic while `O^(-2)` is endotherimic elemnts (or) IONS having inert gas configuration are highlystable in this process a large amount of energy is released but in the CASE of the formation of `O^(-2)` replusions exist between the added electron and already existingh `O^(-1)` ion .sothis process require supply of energy to overcome this repulsion .HENCE the formatoin of `O^(-2)` is an endothermic process | |
| 2049. |
"All alkalis are bases, but not all bases are alkalis”. Justify this statement. |
| Answer» Solution :BASES react with acids to NEUTRALISE them. Some are insoluble. Soluble bases are called Alkalis. For example CuO (copper OXIDE) does not dissolve in water, therefore it.s a base. Generally hydroxides of ALKALI metals and alkaline earth metals are called alkalis. | |
| 2050. |
All acids contain one or more hydrogen atoms, but not all substances containing hydrogen are acids. Support this statement with examples. |
| Answer» Solution :HCl (hydrochloric acid), `H_2SO_4` (sulphuric acid) and `HNO_3` (Nitric acid) are all examples of inorganic acids. They all have the HYDROGEN atom in common. Most acids essentially contain ONE or more hydrogen atoms. Whereas water `(H_2O)` also contains hydrogen, but it is not an acid. Similarly molecule of methane and AMMONIA also contain hydrogen, but all these do not produce `H^+` ions in aqueous solutions. Therefore it can be SAID that all acids contain hydrogen, but all substances containing hydrogen are not acids." | |