List of top Questions asked in PSEB XII

How many unpaired electrons are present in Fe$^{+3}$, Zn$^{+2}$ and Mn$^{+2}$ ?

Explain why Cu$^{+2}$ salts are coloured while Zn$^{+2}$ salts are colourless ?

Calculate the molar conductance $\Lambda_m^\circ$ for CaCl$_2$, given that $\lambda^\circ(Ca^{+2}) = 119.5$ S cm$^2$ mol$^{-1}$ and $\lambda^\circ(Cl^-) = 76.3$ S cm$^2$ mol$^{-1}$.

Calculate the half-life time of a first order reaction having K=8min$^{-1}$.

The rate constant for a first order reaction is 60 sec$^{-1}$. How much time will it take to reduce the concentration of the reaction to 1/10$^{th}$ of its initial value ?

18 gm of glucose (C$_6$H$_{12}$O$_6$) is dissolved in 1 kg of water in a saucepan. At what temperature will the water boil at 1.013 bar pressure ? K$_b$ for water is 0.52 K kg mol$^{-1}$.

The oxidation state of Fe in [Fe(CN)$_6$]$^{-3}$ :

It has been observed that nucleus of a living cell is responsible for this transmission of inherent characters, also called heredity. The particles in the nucleus of cell, responsible for heredity, are called chromosomes, which are made up of proteins and another type of biomolecules called nucleic acids. These are mainly of two types, the deoxyribonucleic acids (DNA) and ribonucleic acid (RNA). Since nucleic acids are long chain polymers of nucleotides, so they are also called polynucleotides. RNA molecules are of three types and they perform different functions. They are named as messenger RNA (m-RNA), ribosomal RNA (r-RNA) and transfer RNA (t-RNA).

Read the following paragraph and answer the questions given below :
It has been observed that nucleus of a living cell is responsible for this transmission of inherent characters, also called heredity. The particles in the nucleus of cell, responsible for heredity, are called chromosomes, which are made up of proteins and another type of biomolecules called nucleic acids. These are mainly of two types, the deoxyribonucleic acids (DNA) and ribonucleic acid (RNA). Since nucleic acids are long chain polymers of nucleotides, so they are also called polynucleotides. RNA molecules are of three types and they perform different functions. They are named as messenger RNA (m-RNA), ribosomal RNA (r-RNA) and transfer RNA (t-RNA).

Give three differences between Lanthanoids and Actinoids.

Transition metals form alloys with other metals. Explain.

Compare the acidic character of Primary, Secondary and Tertiary alcohol.

Explain Reimer Tiemann reaction of Phenols.

Why is aniline less basic than ethylamine ?

Write the Nearest equation and calculate the e.m.f of the following cell at 298K.
Fe(s) | Fe$^{2+$(0.001M) || H$^+$(1M) H$_2$(1atm) | Pt.
Given E$^\circ_{Fe^{+2}/Fe} = -0.44$ V.}

Write the reaction: (i) Wurtz-fitting reaction (ii) Ullmann reaction (iii) Gattermann reaction (iv) Hunsdiecker reaction (v) Balz-Schiemann reaction

Write four differences between SN$^2$ and SN$^1$ reaction.

Define Optical activity.

Why do Zr and Hf exhibit similar properties ?

Give two differences between ideal and non-ideal solution.

Calculate the molal elevation constant of water, it being given that 0.1 molal aqueous solution of a substance boils at 100.052$^\circ$C.

Give two differences between Galvanic Cell and Electrolytic cell.

How many Coulombs of electricity are required for complete oxidation of 90 gm of H$_2$O ?

Give two differences between order of reaction and molecularity of reaction.