ChemistryChemistry QuestionsTop 100 Chemistry Questions for CBSE Class 5 to 12

Top 100 Chemistry Questions for CBSE Class 5 to 12

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Following are the top 100 Chemistry Questions students should practice for important exams –

In which of the following pair size of I element is higher than II element ?

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    common name of the following compound is?

    At 10°C, the osmotic pressure of urea solution was formed to be 500 mm. The solution is diluted ‘x’ times and the temperature raised to 25°C when the osmotic prssure was noticed to be 105.3mm, then ‘x’ is

    Number of ‘d’ electrons in thorium are

    In which of the following compounds, all the bond angles are same.

    The IUPAC name of the given structure (CH 3 ) 2 CH–CH(CH 3 ) 2 is

    What is the activation energy for a reaction if its rate doubles when the temperature is raised from 20°C to 35°C? R = 8 .314 Jmol − 1 K − 1

    Statement I : Melting points of Alkaline earth metals are lower than those of corresponding Alkali metals Statement II : Metallic bonding is weaker in IIA group elements than IA group elements.

    In which all H-atoms are called as chemically equivalent?

    For the following reactions Which of the following statements is correct?

    Most polar bond among the following is

    The product (Y) of the following sequence of the reactions would be

    The oxidation state shown by stroncium is

    Which of the following pairs can be distinguished by the action of heat?

    A metal has a fcc lattice. The edge length of the unit cell is 404 pm. The density of the metal is 2.72 g cm − 3 The molar mass of the metal is N A Avogadro’s constant = 6.02 × 10 23 mol − 1

    A graph showing variation of osmotic pressure (n) versus molar concentration (C) of an aqueous solution at temperature T is given below: The slope of the line doesn’t represent:

    The rate constant k, for the reaction N 2 O 5 ( g ) 2 NO 2 ( g ) + 1 2 O 2 ( g ) is 2 .3 × 10 − 2 s − 1 . Which equation given below describes the change of [ N 2 O 5 ] with time? [ N 2 O 5 ] 0 and [ N 2 O 5 ] t correspond to concentration of N 2 O 5 initially and at time, t?

    A, B, C, D and E are the elements belonging to 13 th group of Modern periodic table. The correct atomic radius trend for these elements is A< B <C < D< E . The element ‘C’ in the sequence is

    Matrix Match Type

    If E Fe + 2 / Fe 0 = x 1 V ; E Fe + 3 / Fe + 2 0 = x 2 V , E Fe + 3 / Fe 0 is

    Which of the following is incorrect

    Total number of alkadienes possible with the formula, C 4 H 6 is

    According to IUPAC, what is the systematic name of the compound shown below?

    Which of the indicated H in the given molecule is most acidic

    Which one of the following is not prepared from halide by chemical oxidation process

    Iron carbonyl, Fe CO 5 is

    2CuI →Cu + CuI 2. This reaction is

    Ratio of hybrid orbitals to pure ‘p’ orbitals in Ethene molecule is

    Which one of the following belongs to representative group of elements in the periodic table

    A gaseous mixture contains 8 grams of oxygen, 14 grams of Nitrogen, 9 grams of water vapour. Partial pressure of water vapour in the mixture is (Assume water vapour behaves like ideal gas)

    Among the following groups of oxides, the group containing oxides that cannot be reduced by carbon to give the respective metals is

    Although, nitrogen does not adsorb on a surface at room temperature, it adsorbs on the surface at 83 K. Which one of the following statements is correct ?

    Which of the facts regarding kinetic energy (E k ) of 8g O 2 , 8g of N 2 and 8g CO 2 each at 273 K, is correct ?

    BiCl 3 + H 2 O A + B . I f B molecular weight is 36 . 5 , what is t h e n a m e o f c o m p o u n d A

    An amphoteric oxide which can act like best oxidizing agent among the following is

    After diwali, in the atmosphere of Delhi most common air pollution is smog . Which is correct for that smog?,,

    Conjugate base for Bronsted acids H 2 O and HF are

    IUPAC name of

    The second ionisation energy is always higher than the first ionisation energy because the

    For the following compounds, the correct statement(s) with respect to nucleophilic substitution reactions is(are )

    The number of chiral centers present in 3,4-dibromo-2-pentanol is

    A l C l 3 on hydrolysis gives ?

    Strongest nucleophile is

    Select the incorrect statement out of the following

    Hydrocarbon which is liquid at room temperature is

    IUPAC Name of the following compound is

    , The EMF of the cell, Zn | Zn 2+ (0.1M) || Cu 2+ (0.01M) | Cu is

    Total number of faces in SF 5 ⊕ ion polyhedron is

    A certain salt (X) gives the following tests (i) Its aqueous solution is alkaline to litmus. (ii) On strongly heating it swells to give a glassy bead. (iii) When concentrated sulphuric acid is added to a hot concentrated solution of (X), crystals of H 3 BO 3 separate out. Identify the colour of these crystals.

    Which technique is used in the extraction of aluminium from bauxite?

    The total energy of electron in an atom is a combination of potential energy and kinetic energy. If total energy is –E for an electron in an atom, then its K.E. and P.E. respectively are

    Which of the aqueous solution turns blue litmus red?

    The bond angle in PH 3 is

    Ionic bonds will be formed more easily between elements with comparatively

    Number of sigma bonds in XeO 3 molecule is/are ‘X’. Number of pπ – pπ bonds in chlorate ion is/are ‘Y’. Difference between X and Y is

    In which of the fallowing molecule have fourth highest enthalpy of formation ( ∆ H f ) of in 15 th group hydrides( EH 3 ) A=NH 3 , B= PH 3 , C=AsH 3 , D= SbH 3 E= BiH 3

    Which bond angle θ would result in the maximum dipole moment for the triatomic molecule YXY ?

    When pressure is low, the fraction of the surface covered during adsorption follows:

    CH 4 ( g ) + 2 O 2 ( g ) ⟶ CO 2 ( g ) + 2 H 2 O ( g ) According to the above chemical reaction, following information have been given. (i) One mole of CH 4 (g ) reacts with two moles of O 2 (g) to give one mole of CO 2 ( g ) and two moles of H 2 O (g) (ii) One molecule of CH 4 (g) reacts with 2 molecules of O 2 ( g ) to give one molecule of CO 2 ( g ) and 2 molecules of H 2 O ( g ) (iii) 22.4 L of CH 4 (g ) reacts with 45.4 L of O 2 to give 22.7 L of CO 2 ( g ) and 45.4 L of H 2 O ( g ) (iv) 16 g of CH 4 (g ) reacts with 2x 32 g of O 2 (g ) to give 44 g of CO 2 ( g ) and 2x 18 g of H 2 O ( g ) From these information the true interconversion should be

    Statement 1: In certain cases metals have a characteristic colour and lustre. Statement 2: Free electrons are present in metals.

    Which of the following change represents a disproportionation reaction(s)

    Assertion(A): specific charge of α − particle is twice to that of proton. Reason(R): Specific charge is given by e/m.

    Which of the following statements is correct for a lyophilic solution?

    The number of elements known when Mendeleef presented periodic table is

    Maximum pπ – pπ back bonding exists in

    The decreasing order of acidic characters of the following is: I. p-Nitrophenol II. o-Nitrophenol III. m-Nitrophenol IV. Phenol

    The heats of adsorption in physisorption lie in the range (in kj/mol)

    T,B,Z and Q are 17 th group elements of Modern periodic table. The correct trend of acidic strength of their hydrides is HT > HB > HZ > HQ. The element ‘T’ in the sequence is

    In which of the following compounds, the C-Cl bond ionisation shall give most stable carbonium ion?

    Acid rain appears when (I) CO 2 dissolves in rain water. (II) Oxides of sulphur dissolve in rain water. (III) Oxides of nitrogen dissolve in rain water. (IV) Hydrocarbons dissolve in rain water.

    Number of S-O-S bonds in a molecule of Dithionic acid are

    When chains of one kind are attached to the back bone of a different polymer, the co-polymer is called

    When the temperature is raised, the viscosity of liquid decreases, this is because

    Which of the following statements is incorrect about the secondary structure of protein?

    When 100 mL of 1.0 M HCl was mixed with 100 mL of 1.0 M NaOH in an insulated beaker at constant pressure, a temperature increase of 5.7°C was measured for the beaker and its contents (Expt. 1). Because the enthalpy of neutralization of a strong acid with a strong base is a constant (-57.0 kJ mol -1 ), this experiment could be used to measure the calorimeter constant. In a second experiment (Expt. 2), 100 mL of 2.0 M acetic acid (K a = 2.0 × 10 -5 ) was mixed with 100 mL of 1.0 M NaOH (under identical conditions to Expt. 1) where a temperature rise of 5.6°C was measured.(Consider heat capacity of all solutions as 4.2 J g -1 K -1 and density of all solutions as 1.0 g mL -1 )

    Which of the following atom has the highest first ionization energy ?

    The number of nodal planes in a p x orbital is

    C, X, Z, B and D are the elements belonging to 15 th group of Modern periodic table. The correct trend of electronegativity in these elements is C = X < Z < B < D. The element ‘B’ in the sequence is

    From a measurement of the freezing point depression of benzene, the molecular weight of acetic acid in a benzene solution was determined to be 100. The percentage association of acetic acid is

    In a Bohr’s model of an atom, when an electron jumps from n = 1 to n = 3, how much energy will be emitted or absorbed ?

    Following are some of the certain facts of Ostwald’s theory of acid-base indicators. I : Ionised and unionised forms have different colours. II : Colour change is indicated at the end point when unionised form changes to ionised form due to change in pH. III : Benzenoid form changes to quinonoid form and vice-versa due to change in PH. Select the correct facts

    Statement 1: Inert gases are monoatomic. Statement 2: Inert gases have stable configuration.

    Copper matte is a molten mixture of ?

    In which of the fallowing molecule have second minimum bond angle in 15 th group hydrides( EH 3 ) A=NH 3 , B= PH 3 , C=AsH 3 , D= SbH 3 E= BiH 3

    For 10 – 2 M H 3 PO 3 solution which of the following relations is correct ?

    Which of the following compound can show tautomerism ?

    Statement-I: α -D(+) -glucopyranose and β -D(+)-glucopyranose are enantiomers. Statement-II: Melting point of β -D(+)-glucopyranose is higher than that of α -D(+) -glucopyranose.

    If the formation of diatomic boron molecule is predicted based on MO theory, the bond order would be

    The first organic compound prepared in the laboratory from its elements was

    Which of the following are anionic detergents? I. Sodium salts of sulphonated long chain alcohol. II. Ester of stearic acid and polyethylene glycol. III. Quaternary ammonium salt of amine with acetate ion. IV. Sodium salts of sulphurated long chain hydrocarbons. The correct option is

    The IUPAC name of the coordination compound K 3 Fe CN 6 is:

    18 C–H and 7 C–C sigma bonds are in

    Statement-I: KMnO 4 oxidises Potassium iodide to Potassium periodate in faint alkaline medium Statement-II: In permanganometric titrations carried out in acidic medium, HCl is used as medium.

    The product of the following reaction is CaO + P 4 O 10 ……

    Vapour pressure of pure A is 70 mm of Hg at 25 o C.It forms an ideal solution with ‘B’ in which mole fraction of A is 0.8. If the vapour pressure of the solution is 84 mm of Hg at 25 o C the vapour pressure of pure B at 25 o C is

    The order of boiling points of four equimolar aqueous solutions is C < B < A < l). The correct order of their freezing points is

    The empirical formula of permutit or zeolite used in ion-exchange method is

    Which one of the following hydride is least volatile

    Which one of the following pairs of species have the same bond order?

    The Van’tHoff factor for 0.1 M Ba(NO 3 ) 2 solution is 2.74. The degree of dissociation is

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