SECTION - B [CHEMISTY - NUMERIC] - JEE STD 11 Science Questions

Question 14 Marks

20 mL of 2 M NaOH solution is added to 400 mL of 0.5 M NaOH solution. The final concentration of the solution is _________$\times 10^{-2} M$. (Nearest integer).

Answer

(57)
Sol. $M _{ F }=\frac{ M _1 V_1+ M _2 V_2}{V_1+ V _2}$
$\begin{array}{l}=\frac{2 \times 20+0.5 \times 400}{420}=0.571 M \\ =57.1 \times 10^{-2} M \\ =57\end{array}$

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Question 24 Marks

Consider the following cases of standard enthalpy of reaction $\left(\Delta H _{ r }^{ o }\right.$ in $\left.kJ mol ^{-1}\right)$$
\begin{array}{l}
C_2 H_6(g)+\frac{7}{2} O_2(g) \rightarrow 2 CO_2(g)+3 H_2 O(\ell) \Delta H_1^{\circ}=-1550 \\
C \text { (graphite })+O_2(g) \rightarrow CO_2(g) \Delta H_2^{o}=-393.5 \\
H_2(g)+\frac{1}{2} O_2(g) \rightarrow H_2 O(\ell) \Delta H_3^{o}=-286
\end{array}
$
The magnitude of $\Delta H _{ fC _2 H _6(g)}^o$ is _________ $kJ mol ^{-1}$ (Nearest integer).

Answer

(95)
Sol.
$\begin{array}{ll}\text { } 2 C _{\text {(graphite) }}+3 H _2(g) \rightarrow C _2 H _6(g) \Delta H _{ f }=\text { ? } \\ C _2 H _6(g)+\frac{7}{2} O _2(g) \rightarrow 2 CO _2(g)+3 H _2 O ( l ) \\ \quad \Delta H _1=-1550 \\ C _{\text {(graphite) }}+ O _2(g) \rightarrow CO _2(g) \Delta H _2=-393.5 \\ H _2(g)+\frac{1}{2} O _2(g) \rightarrow H _2 O (/) \Delta H _3=-286 \\ \Delta H _{ f }=2 \Delta H _2+3 \Delta H _3-\Delta H _1 \\ \quad=95 kJ / \text { mole. }\end{array}$

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Question 34 Marks

The complex of $Ni ^{2+}$ ion and dimethyl glyoxime contains _________ number of Hydrogen $( H )$ atoms.

Answer

(14)
Sol.

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Question 44 Marks

Niobium $( Nb )$ and ruthenium $( Ru )$ have "x" and "y" number of electrons in their respective $4 d$ orbitals. The value of $x+y$ is _________

Answer

(11)
Sol.$\quad Z=41 \rightarrow Nb$ (Niobium) : $[ Kr ]_{36} 4 d^4 5 s^1$
Number of electron in $4 d=4=x$
$Z =44 \rightarrow Ru$ (Ruthenium) $[ Kr ]_{36} 4 d^{7} 5 s^1$
Number of electron in $4 d=7= y$
$x+y=11$

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Question 54 Marks

The compound with molecular formula $C _6 H _6$, which gives only one monobromo derivative and takes up four moles of hydrogen per mole for complete hydrogenation has _________$\pi$ electrons.

Answer

(8)
Sol.

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JEE SECTION - B [CHEMISTY - NUMERIC]

SECTION - B [CHEMISTY - NUMERIC]

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