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.
| 1601. |
Helium atom has an atomic mass of 4 u and two protons in its nucleus. How many neutrons does it have ? |
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Answer» Solution :NUMBER of NEUTRONS = Atomic mass - Number of PROTONS THEREFORE, the number of neutrons in the ATOM `= 4-2=2` |
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| 1602. |
he number of atoms in a molecule of the elementary substance is called ___ |
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Answer» |
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| 1603. |
Hardness of steel increases with the increase of _______________. |
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| 1604. |
H_5PO_4 serves as very important intermediate in fertiliser industry. Justifiy |
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Answer» Solution :(i) reaction of `H_2PO_4` with MINERAL phosphate and AMMONIA (II) composition of phosphate rock. (iii) solubility of the MAJOR component of the phosphate rock (iv) reaction between `H_3PO_4` and the above component (v) solubility of the product formed (vi) reaction between `H_3PO_4` and ammonia (vii) soluble nature of the product formed |
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| 1605. |
H_2SO_4 is always diluted by adding it to water but not by adding water to it. Justify. |
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Answer» Solution :(i) ENERGY CHANGES involved in the reaction between `H_2SO_4and H_2O` (II) conditions REQUIRED for CONTROLLING the reaction |
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| 1606. |
Gunpowder is a ________. |
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Answer» solid-liquid homogeneous MIXTURE |
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| 1608. |
_________group elements have greater tendency to form cationns |
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| 1610. |
Green plants absorb .......... in the presence of .............. to make their food |
| Answer» SOLUTION :`CO_(2)`,SUNLIGHT | |
| 1611. |
Graphite is generally used as a refractory material in electric furnaces because. |
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Answer» of its HIGH melting POINT |
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| 1612. |
Graphite cannot be used as a lubrican in space' Give reasons. |
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Answer» Solution :(i) layered structure of GRAPHITE (ii)factors that make graphite act a LUBRICANT (III) conditions in space (IV) relate conditions in space to factors that help graphite to act as a lubricant. |
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| 1613. |
Graphite and iodine are the onyl non-metals possessing lustr which is actually an important attribute of metals. Comment on the statement with proper justification. |
| Answer» Solution :The reason behind the lustre of metal is the presence of free electrons which undergo excination and deexcination in the visible region of spectrum. IODINE being LARGER atom, electrons can udergo excination and deexcination in the visible region, since they experience less nuclear forces of attraction.Graphite in the LAYER lattice sturcture has free electrons.which can show the same trend. Due to these reasons, these TWO non-metals exhibit lusture LIKE metals. | |
| 1614. |
Graphene is one atom thick layer of carbon obtained from _________ . |
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Answer» diamond |
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| 1616. |
Global warming is caused by the excessive presence of ................ in air. |
| Answer» SOLUTION :`CO_(2)` | |
| 1618. |
Given the names of some abnormal climatic situations that are now being felt on the earth . |
| Answer» Solution :(i) GLOBAL warming , (II) GREENHOUSE EFFECT and (iii)DEPLETION of ozone layer | |
| 1619. |
Given reasons for the following observation. The smell of hot sizzling food reaches you several meters away, but to get the smell from cold food you have to go close. |
| Answer» SOLUTION :SOLID DIFFUSE at very rate. But if the temperature of the solid is increased, then the rate of diffusion of the solid PARTICLES into air increases. This is due to an increase in the kinetic energy of solid particles. Hence thesmell of hot sizzling food reaches us even at a distance, bu to the smell from COLD food we have to go close. | |
| 1620. |
Given below is the graph representing the ionsiation energies of a few element ,A to H with successive atomic number (a) identify the noble gas (b) which of the following elements could Dbe? (c ) which element has the highest electron affinity (d) Which element has the stongest metallic character? (e ) write the unit of ionisation energy |
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Answer» SOLUTION :(a) The noble gas is C (b)D is an alkali metal i.e Na (c ) B has the HIGHEST electron affinity (d) D has the STONGEST metallic character (e ) The UNIT of ionisation energy is kj/mole |
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| 1621. |
Give two reasons to justify- (a) Water at room temperaure is a liquid (b) an iron almirah is a solid at room temperature. |
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Answer» Solution :(a) The two general properties of liquids are that liquids have 'a fixed volume' but 'no fixed shape'. Now, water is a liquid at ROOM temperature because : (i) water has a fixed volume (which does not change on changing its container). (ii) water has no fixed shape (it TAKES the shape of the container in which it is kept). (b)The two general properties of solids are that solids have 'a fixed shape' and 'a fixed volume'. An almirahis a SOLID at room temperature because : (i) an almirah has a fixed shape (which cannot be changed by pressing it with HANDS). (ii)an almirah has a fixed volume (which depends on the dimensions ACCORDING to which it is made). |
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| 1622. |
Give reasons to justify. Water at room temperature is a liquid. |
| Answer» Solution :WATER at room TEMPERATURE is a liquid if we CONSIDER the temperature of the room is `27^(@)C`. Water TURNS into solid at `0^(@)C` and into gas at `100^(@)C`. So it is obvious that water at room TEMPARATURE is a liquid. | |
| 1623. |
Give two reasons to justify- Aniron almirah is a solid at room temperature |
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Answer» SOLUTION :An IRON almirah is a SOLID at ROOM temperature (i) An almirah has a fixed shape and a fixed volume (ii) It cannot flow hence it is RIGID. |
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| 1624. |
Give two examples of polyatomic molecules. |
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Answer» Solution :`K_(2)SO_(4)` (7 molecules) and `C_(2)H_(6)` (8 molecules) are the examples of POLYATOMIC molecules. [Note : `C_(2)H_(6)` is ethane gas.] |
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| 1625. |
Give two examples from daily life where Tyndall effect is observed. |
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Answer» Solution :The examples of Tyndall EFFECT are as follows: (1) Scattering of light by dust particles suspended in air. (2) In dense forest, tiny WATER droplets are suspended in air in the EARLY morning. These droplets scatter the beam of light. |
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| 1626. |
Give the symbols of the following elements : Copper, Iron, Lead, Potassium, Silver |
Answer» SOLUTION :
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| 1627. |
Give the structural formulae of four compounds of the homologous series succeeding the one having molecular formula C_3H_4.Also give their molecular wieghts. |
| Answer» SOLUTION :CHARACTERISTICS of HOMOLOGOUS SERIES | |
| 1628. |
Give the significance of pH of soll in agriculture. |
| Answer» Solution :In AGRICULTURE, the PIT of soil in very important. CITRUS FRUITS require slightly alkaline soll, will rice requires acidic soil and sugarcane requires neutral soil. | |
| 1629. |
Give the number of valece electorns of (a) alkali elements and (b) halogens |
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| 1630. |
Give the names of the elements present in the following compounds : (a) Quick lime (b ) Hydrogen bromide (c) Baking powder (d) Potassium sulphate |
Answer» SOLUTION :
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| 1631. |
Give the name of elements present in the Quick limecompound. |
| Answer» SOLUTION :CALCIUM and OXYGEN | |
| 1632. |
Give the name of elements present in the Potassium sulphate compound |
| Answer» SOLUTION :POTASSIUM , SULPHUR and OXYGEN | |
| 1633. |
Give the name of elements present in the Hydrogen bromide compound . |
| Answer» SOLUTION :HYDROGEN and BROMIDE | |
| 1634. |
Give the name of elements present in the Baking powder compound |
| Answer» SOLUTION :SODIUM , HYDROGEN , CARBON , OXYGEN | |
| 1635. |
Give the limitations of dobereiner's classification |
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| 1636. |
Give the evidence for the existence of nucleus in an atom. |
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| 1637. |
Give the equation for the lab preparation of hydrogen. |
| Answer» SOLUTION :`Zn+underset(("DILUTE"))(2HCL)toZnCl_(2)+H_(2)`. | |
| 1638. |
Give the differences between physical and chemical changes. |
Answer» SOLUTION :
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| 1639. |
Give the arrangement of electrons of the following elements in their orbit : ""_(11)Na, ""_(13)Al, ""_(19)K, ""_(16)S, ""_(8)O |
Answer» SOLUTION :
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| 1640. |
Give the applications of chromatography. |
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Answer» Solution :APPLICATIONS of chromatography are : (1) to separate colours in a dye. (2) to separate PIGMENTS from NATURAL colours. (3) to separate drugs from BLOOD. |
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| 1641. |
Give some example of doberienter 's triads .Explain how they are grouped as triads |
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| 1642. |
Give scientific reasons for the following statements : The weight of 100 g H_(2) and He is same yet the number of elements is not same. |
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Answer» Solution :The number of atoms in a molecule (compound) depends on mole number and ATOMICITY. `rarr` Mole of 100G `H_(2) = (100 g)/(2 u)` = 50 mole `:.` Number of atoms in 100 g `H_(2) = 2 xx 50 xx 6.022 xx 10^(23)` `= 6.022 xx 10^(24)` atoms `rarr` Mole of 100 g He = `(100g)/(4 u)` = 25 mole `:.` Number of atoms in 100 g He = `1 xx 25 xx 6.022 xx 10^(23)` = `150.55 xx 10^(23)` = `1.5055 xx 10^(25)` atoms Thus, the molc and atomicity of both the gases are DIFFERENT, the number of atoms is not same. |
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| 1643. |
Give scientific reasons for the following statements : The chemical properties of a rod and wire of iron are identical but the chemical properties of silver ring are different. |
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Answer» Solution :According to postulates of Dalton.s atomic theory, atoms in a given element are IDENTICAL in mass and chemical PROPERTIES. There are the atoms of only iron in rod and wire, hence they are identical in mass and chemical properties. `RARR` According to postulate of Dalton.s atomic theory, atoms of different ELEMENTS have different masses and chemical properties. Iron and silver are two different elements, hence their chemical properties are different. |
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| 1644. |
Give scientific reasons for the following statements : Both CO_(2) and NH_(3) are gases, but their atomicity is different. |
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Answer» Solution :The NUMBER of ATOMS constituting a molecule is known as its atomicity. `rarr` Moreover the valency of all ELEMENTS is not same. `rarr` The atomicity of `CO_(2)` is THREE, while that of `NH_(3)` is FOUR. |
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| 1645. |
Give reasons. We can easily move our hand in air but to do the same through a solid block of wood we need a karate expert. |
| Answer» Solution :Particles of the air have LARGE spaces between them. On the other hand, wood has LITTLE SPACE between its particles. ALSO, it is rigid. For this reason, we can easily MOVE our hands in the air, but to do the same through a solid block of wood, we need a karate expert. | |
| 1646. |
Give reason for the following observations. We can get the smell of perfume sitting several metres away. |
| Answer» Solution :The particles perfume DIFFUSE RAPIDLY into the air and its SMELL can be smelt while sitting SEVERAL meters away. | |
| 1647. |
Give reasons : Reagent silver nitrate is not prepared in tap water. |
| Answer» Solution :TAP water contains dissolved `Cl_(2)`, so formation of PPT. of AGCL spoils the reagent. | |
| 1648. |
Give reason for the following observations. Naphthalene balls disappear with time without leaving any solid. |
| Answer» Solution :Napthalene balls undergo sublimation due to which it converts DIRECTLY into vapour and DISAPPEAR into AIR without leaving any SOLID. | |
| 1649. |
Give reasons : On boiling, water loses its taste. |
| Answer» SOLUTION :On HEATING, gases DISSOLVED in water are expelled. TASTE of water is due to dissolved gases, so water loses its taste. | |
| 1650. |
Give reasons : It is difficult to find absolutely pure water in nature. |
| Answer» SOLUTION :WATER is a universal SOLVENT. It DISSOLVES nearly all the substances. | |