11th Class Chemistry Important Short Question Online Free


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  • 11th Class Chemistry Ch 1 Basic Concepts Short Question Answers
  • 11th Class Chemistry Ch 2 Experimental Techniques in Chemistry Short Question Answers
  • 11th Class Chemistry Ch 3 Gases Short Question Answers
  • 11th Class Chemistry Ch 4 Liquids and Solids Short Question Answer
  • 11th Class Chemistry Ch 5 Atomic Structure Short Question Answers
  • 11th Class Chemistry Ch 6 General features of Chemical bond Short Question Answer
  • 11th Class Chemistry Ch 7 Thermochemistry Short Question Answers
  • 11th Class Chemistry Ch 8 Chemical Equilibrium Short Question Answers
  • 11th Class Chemistry Ch 9 Solutions Short Questions Answers
  • 11th Class Chemistry Ch 10 Electro Chemistry Short Questions Answer
  • 11th Class Chemistry Ch 11 REACTION KINETICS Short Question Answers

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11th Class Chemistry Important Short Question

  • Define Fahrenheit scale.
  • What is conjugate base of the acid?
  • Define Evaporation,
  • A weak acid has strong conjugate base. Justify.
  • Explain why evaporation takes place at all temperatures.
  • Define hydrolysis with example.
  • Voltaic cell is reversible cell, State.
  • Differentiate between hydration and hydrolysis
  • What are isotopes? Why they have same chemical but different physical properties?
  • What is mole? Why the sum of mole fractions of all components of a solution is always equal to unity?
  • Define the octet rule.
  • Define state of Equilibrium.
  • What is the basic principle of crystallization?
  • Define amorphous solids.
  • Define optimum pH?
  • What is vaccum distillation?
  • Define polarizability.
  • What is Lyman series?
  • Define Balmer series.
  • Define unit cell.
  • Define vander wall’s equation.
  • Justify that heat of formation of compound is sum of all the other enthalpies.
  • Why is HF a weaker acid than HC1?
  • Calculate the density of methane at STP.
  • What are London dispersion forces?
  • What do you mean by chemical equilibrium?
  • Why regular air cannot be used in diver’s tank?
  • What is the first law of thermodynamics?
  • Give two statements of Raoult’s law.
  • Why the dipole moment of SO2 is 1.61 D but that of SO3 is zero?
  • The dipole moments of CO2 and CS2 are zero but that of SO2 is 1.61D.
  • What are dipole-dipole forces of attraction? Explain with an example.
  • What is the basic assumption of VSEPR theory, and discuss the shape of a molecule (BF3) containing three electron pairs?
  • Define the term state function, give two examples.
  • Write down two postulates of VSEPR theory.
  • State the geometry of NH3 molecule on the basis of VSEPR theory.
  • Explain the term enthalpy.
  • The enthalpy of neutralisation of all the strong acids and strong bases has the same value. Justify.
  • State enthalpy of combustion with example.
  • Explain the term enthalpy of atomization.
  • State Le-Chatelier’s principle and discuss the effect of change in concentration of a product on reversible reaction.
  • Explain the term buffer capacity.
  • Give the two applications of the solubility product.
  • How the type of bonding affects solubility of compounds?
  • What are buffer solutions? How a basic buffer can be prepared?
  • Write two uses of buffer solution.
  • Define solubility product. Give its one application.
  • Depression in freezing point is a colligative property. Justify.
  • What is meant by molality? Give its formula.
  • Why Beckmann’s thermometer is used to measure the depression in freezing point?
  • Why the NaCt and KNO3 are used to lower the melting point of ice?
  • What is electrochemical series?
  • Lead accumulators is a chargeable battery. Justify.
  • How electrochemical series help us in determining the chemical reactivity of metals?
  • What is difference between cell and battery?
  • Differentiate between average rate and instantaneous rate.
  • Why different liquids evaporate at different rates even at the same temperature?
  • What is specific rate constant or velocity constant?
  • How surface area affects the rate of a chemical reaction?
  • What happens to the rate of a chemical reaction with the passage of time?
  • What are enzymes? Give two examples in which enzymes act as catalyst.
  • Why theoretical yield is greater than actual yield?
  • Enzymes are specific in action. Justify.
  • Law of conservation of mass has to be obeyed during stoichiometric calculation, give reason.
  • What is vapour pressure? OR What is Dalton’s law of partial pressure?
  • Write down stoichiometric assumptions.
  • Write down the values of atmospheric pressure in four different units.
  • What will be the effect of change of pressure on the synthesis of NH3?
  • Lowering of vapor pressure is colligative property. Explain.
  • Derive the units for gas constant R in general gas equation when pressure is in Nm-2 and volume in m3.
  • What is the size of atom?
  • What are defects in Rutherford’s atomic model?
  • Why cationic radius radius is smaller than parent atom?
  • Why the radius of an atom cannot be determined precisely?
  • Why is the -radius of a cation smaller than its parent atom?
  • Mg atom is twice heavier than that of carbon atom. Justify.
  • The radius of first orbit of hydrogen atom is 0.529 A°. Calculate the radius of 3″1 orbit of hydrogen atom.
  • Give the chemistry of electrolysis of aqueous solution of sodium chloride.
  • What are the defects in Rutherford’s atomic model?
  • Write the electronic configuration of Cr for which atomic number is 24.
  • Write electrode reactions of electrolysis of fused sodium chloride.
  • Define autocatalysis with an example.
  • What are isotherms?
  • Define Avogadro’s law.
  • Give assumption of stoichiometry.
  • Why is there a need to crystallize the crude product?
  • Define transition temperature with an example.
  • Write down the electronic configuration of Fe (26) and Br (35).
  • Transition temperature is the term used for elements as well as compounds. Explain
  • Give any two properties of neutrons. OR How neutrons were discovered by Chadwick? Give the equation of nuclear reaction involved.
  • What do you know about internal energy of a system?
  • State Hund’s rule and give an example.
  • Define activation energy and activated complex.
  • What is lattice energy? Give an example.
  • What is electrolytic cell? What is the difference between metallic conduction and electrolytic conduction?
  • Impure copper can be purified by electrolytic process. Explain.
  • Differentiate between electrolytic and voltaic cell.
  • Define standard electrode potential.
  • Give chemical reactions taking place at anode and cathode in a fuel cell.
  • Write down any two characteristics of enzyme catalysis.
  • How fuel cells produce electricity?
  • Define order of reaction. Give one example.
  • Differentiate between Enothermic and Endothermic Reaction.
  • What is half life method for the determination of order of a reaction?
  • Define half life period. How is it used to determine the order of reaction?
  • Differentiate between endothermic and exothermic reactions.
  • How the values of equilibrium constant helps to predict the direction of a reversible reaction?
  • The sum of the coefficients of a balanced chemical equation is not necessarily important to give the order of reaction justify.
  • Radioactive decay is first order reaction. Justify.
  • How the direction of a reversible reaction at any instant can be determined by Kc value?
  • How the value of K, of a reaction helps to predict the direction of a reversible reaction?
  • Define order of reaction with the help of an example.
  • Define a spontaneous reaction.
  • Write a nuclear reaction for the decay of free neutron.
  • Why oxygen cannot be determined directly in combustion analysis?
  • Write down nuclear reactions involved in the conversion of Cu into Zn.
  • Write function of Mg (C CO-4)2 and KOH in combustion analysis.
  • Define molecular ion, write its uses.
  • What iS Boiling point? Why boiling point of H2O is greater than HF?
  • Boiling needs a constant supply of heat, why? Why the boiling points of noble gases increase down the group?
  • Differentiate between inter molecular forces. Differentiate between ion and molecular ion.
  • State Moseley’s law. Write two importance of Moseley law.
  • Define Pauli’s Exclusion Principle with an example.
  • What is common ion effect? Give an example.
  • Differentiate between Zeeman effect and stark effect.
  • State Auf-bau principle and Pauli’s exclusion principle. State Pauli Exclusion Principle and Hunt’s rule.
  • State Joule Thomson effect. Write its application.
  • Give statement of ‘Distribution Law’.
  • The electrical conductivity of metals decrease with the increase in temperature. Why?
  • Mention two defects of Bohr’s model. According to Bohr’s model’ in which orbit electron can move?
  • Define upper consulate temperature with example.
  • How the wave nature of electron was verified experimentally? Explain electron gas theory.
  • Differentiate between homogeneous catalysis and heterogeneous catalysis.
  • Diamond is insulator and hard. Give reason. Diamond is hard and an electrical insulator. Give reason.
  • What is difference between qualitative analysis and quantitative analysis?
  • State spin quantum number (s) briefly. What is Planck’s quantum theory?
  • Cathode rays are material particles. Explain with reason. Why of cathode rays is equal to that of electrons?
  • Whichever gas is used in the discharge tube, the nature of the cathode rays remains the same. Why?
  • Why the nature of cathode rays is independent of the nature of the gas used in discharge tube?
  • How the K-series, L-series and M-series of x-rays spectrum are produced?
  • Define ionization energy and write its variation in the periodic table.
  • Give reason for the production of positive rays. OR Why — value for the cathode rays is just equal to that of electron?
  • Name the factors which affect the ionization energy of an element.
  • Why ionization energy decreases down the group although the nuclear charge increases?
  • How does ionization energy vary in a group of periodic table?
  • Define electronegativity. Give its trend in the periodic table.
  • The bond angles of H20 and NH3 are not 109.5° like that of CH4. Although 0-atom and N-atom are SP3 hybridized like C- in CH4, give reason.
  • Explain the term bond order. OR What is Bond Energy?
  • The bond angles of H2O and NH3 are not 109.5° like that of CH4 although oxygen and nitrogen atoms are SP3 – hybridized. Why?
  • How the nature of a chemical bond is predicted with the help of electronegativity values of two bonded atoms?
  • Define coordinate covalent bond and give one example. OR it-bonds are more diffused than a-bonds. Give reason.
  • Why n-bonds are more diffused than a-bonds? OR NH 3 and N F Shave different bond angles. Justify.
  • Define bond order. Calculate bond order of hydrogen molecule.
  • Define bond energy with two parameters which determine its strength.
  • What is mass spectrum? OR Why atomic spectrum isline spectrum?
  • Define empirical formula and molecular formula with example. Write four steps for determining empirical formula.
  • Define spectrums. OR What is the difference between continuous spectrum and line spectrum?
  • Define molecular formula of a compound. How is it related with its empirical formula? OR What Gram formula?
  • What is solvent extraction?
  • Boiling points of the solvents increase due to the presence of solutes. Justify it.
  •  Why is the vapour pressure of a solution less than pure solvent?
  • Calculate the value of R in SI unit. OR Calculate the value of gas constant It in SI-units.
  • Write down the name of Eight solvent used in crystallization. OR Define distribution law and how it is helpful in solvent interaction.
  • Give four fundamental postulates of kinetic molecular theory of gases.
  • Write two faulty assumptions of kinetic molecular theory of gases.
  • Derive Graham’s law of diffusion in the light of kinetic molecular theory of gases.
  • Write down the faulty postulates of kinetic molecular theory of gases.
  • Why one feels sense of cooling under the fan after bath?
  • Explain Boyl’s law according to kinetic molecular theory of gases.
  • Explain with reason, “Evaporation causes cooling.” OR One feels sense of cooling under the fan after bath. Explain with reason.
  • Write down two applications of liquid crystals.
  • How the liquid crystals help in the detection of the blockage in veins and arteries?
  • Vacuum distillation can be used to avoid decomposition of a sensitive liquid. Explain with reason.
  • Define isomorphism and polymorphism with example.
  • Calculate mass of an electfon from its —e value. m
  • What is the relationship between polymorphism and allotropy?
  • What is mass spectrometer? OR Define relative atomic mass.
  • Define Molar mass. OR State the law of mass action. OR What is Avogadro’s number? Give equation to relate the Avogadro’s number and mass of an element.
  • Calculate fraction of total pressure exerted by oxygen when equal masses of CH4 and 02 are mixed in an empty container at 25°C.
  • Calculate the mass of electron when its e/m value is 1.7588 x 10’1 C
  • Calculate mass in kg of 2.6 x 1020 molecules of SO2. OR No individual neon atom in the sample of the element has a mass of 20.18 amu. Explain with reason.
  • Define orbital. Why the energy of antibonding molecular orbital is higher than corresponding bonding molecular orbitals?
  • State Heisenberg’s Uncertainty Principle and give its mathematical expression.
  • Distribute tk electron in orbitals of 29Cu and 26Fe. OR Justify that the distance gaps between different orbitals go on increasing from the lower to higher orbits.
  • State the Hess’s law of constant heat summation. OR Give statement of Hess’s law.
  • Sketch the molecular orbital picture of 02. OR Define Hydrogen Bonding.
  • Write two applications of equilibribm constant.
  • Define pH and p0H.
  • Water and ethanol can mix in all proportions, give reason. OR What is water of crystallization? Give two examples.
  • One mg of K2CrO4 has thrice the number of ions than the number of formula units when ionized in water, justify.
  • One molal solution of urea in water is dilute as compared to one molar solution of urea but the number of particles bf solute is same. Justify it
  • What is ionic product of water? Define pH.
  • Gasoline evaporates much faster than water. Give reason.
  • The vapour pressure of diethyl ether is higher than that of water at same temperature. Give reason.
  • Water vapours do not behave ideally at 273 K. Justify.
  • Water vapours do not behave ideally at 273 K. Explain
  • What is meant by water of crystallization? Give an example. .
  • Differentiate between adsorption chromatography and partition chromatography.
  • How many molecules of water are there in lOg of ice? OR Ice occupies more space than water, give reason.
  • Define and write the meaning of chromatography.
  • What do you know about Rf value of a component in paper chromatography?
  • Define chromatography. Give, its two uses. OR Differentiate between stationary and mobile phase used in chromatography.
  • Define sublimation. What type of a substance can be purified by this technique?
  • Give the importance of sublimation. OR Define sublimation and partition law.
  • Heat of sublimation of iodine is very high although it is a molecular solid. Give reason.
  • What is sublimation? Give one example of sublime solid.
  • State Boyle’s law of gases.
  • Give two applications of plasma.
  • How the percentage ionic character of a covalent bond is determined by dipole moment?
  • What is plasma state? How is plasma formed at high temperature?
  • Ionic solids do not conduct electricity in solid state. Give reason.
  • How the electronegativity difference of two bonded atom can be used to predict the ionic/covalent nature of the bond
  • No bond in chemistry is 100% ionic. Justify it. OR Why ionic crystals are highly brittle?
  • Why the ionic radius of Cf- ion increases from 99 pm to 181 pm?
  • Ionic crystals are highly brittle. Explain with reason.
  • Differentiate between ideal and non-ideal solutions.
  • Many solutions do not behave ideally. Give reason.
  • Calculate the molarity of a solution containing 9 grams of glucose (C61-11206) in 250 cm3 of solution.
  • Define molal boiling constant with an example.
  • One molal solution of glucose is dilute as compared to one molar solution of glucose. Justify it. OR What is molarity?
  • Salt bridge is not required in lead storage call. Why?
  • Write down reactions taking place at the electrodes on the discharging of Nickle-Cadmium Cell.
  • What is the function of salt bridge in galvanic cell?
  • Calculate the oxidation number of Cr in K2CrO4 and Cr202-2.
  • Find out the oxidation state of Mn in (a) KMnO4 (ii) K2MnO4. OR Calculate oxidation number of chromium in CrCt3.
  • What is poisoning of a catalyst? Give an example. OR How a catalyst is specific in its action?
  • Calculate the oxidation number of `Mn’ in KMnO4.
  • Define and give an example of the process of activation of a catalyst.
  • N2 and CO have same number of electrons, protons and neutrons. Justify.
  • Separate the following molecules as polar or non-polar: (i) CO2 (ii) CH3OH (iii) CC Q4 (iv) HF
  • Why N2 and CO have the same number of protons, electrons and neutrons?
  • Define the term molecule. Give two examples also.

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