NEB Class 12 Science Chemistry Question Paper 2077

Write two important features of hybrid orbitals.

Define the terms: (i) Primary standard solution (ii) Acidimetry

How many coulombs are required to produce $50\,\text{gm}$ of Al when electrode reaction is $Al^{+++}+3e^{-}\rightarrow Al$ (atomic mass of $Al=27$)?

For a reaction, $2N_2O_5 \rightarrow 4NO_2+O_2$, the rate of disappearance of $N_2O_5$ is $4\times10^{-6}\ \text{mol L}^{-1}\text{S}^{-1}$, what will be the rate of formation of $NO_2$?

Write the action of heat on blue vitriol.

Write an example of each of the following: (i) Aldol Condensation (ii) Rosenmund's reduction

Write down the structure of a primary amine and a secondary amine from $C_3H_9N$ and give their IUPAC name.

Define the terms: (i) titration error (ii) unknown solution. What volume of $10\,M$ HCl and $3\,M$ HCl should be mixed to obtain one litre of $6\,M$ HCl solution? $[1+1+3]$

State enthalpy of combustion. If heat of formation of $CO_2$, $H_2O$ and $C_6H_{12}O_6$ are $-395\ \text{KJ mol}^{-1}$, $-269.4\ \text{KJ mol}^{-1}$ and $1169\ \text{KJ mol}^{-1}$ respectively. Calculate the heat of combustion of glucose. $[1+4]$

Give chemical reaction for the preparation of ethanoic acid from (i) 1,1,1-trichloro ethane (ii) Methyl magnesium iodide (iii) ethane nitrile. How is ethanoic acid converted into methanoic acid? $[3+2]$

Write down a structural formula and its IUPAC name of $C_4H_{10}O$. How would you apply Victor Meyer's method for the distinction of propan-1-ol from propan-2-ol? Write an example of the following reactions: (i) oxo-process (ii) Baeyer's test. Convert propan-2-ol into propan-1-ol. $[2+4+2+2]$

Define: (i) rate law equation (ii) Half life period for a reaction. How is order of a reaction differed from molecularity of reaction? The following rate data were obtained for the reaction $2A+B\rightarrow C$:

Calculate the rate of formation of C when $[A]=0.5\ \text{mol L}^{-1}$ and $B=0.2\ \text{mol L}^{-1}$. $[2+4+4]$