0
Q:

# The function of nitrogen in air is

 A) to make air a moderate supporter of combustion B) to maintain the density of air constant C) to prevent the hydrogen in air from exploding D) to reduce the poisonous nature of ozone in air

Answer:   A) to make air a moderate supporter of combustion

Explanation:

If air contained all oxygen and no nitrogen, everything would have burnt off

Subject: Chemistry
Q:

In a face centred cubic lattice, atom A occupies the corner positions and atom B occupies the face centre positions. If one atom of B is missing from one of the face centred points, the formula of the compound is

$\inline \dpi{100} \small 1.\: A_{2}B_{5}$

$\inline \dpi{100} \small 2.\: A_{2}B$

$\inline \dpi{100} \small 3.\: AB_{2}$

$\inline \dpi{100} \small 4.\: A_{2}B_{3}$

 A) Option 1 B) Option 2 C) Option 3 D) Option 4

Explanation:

$\inline \dpi{100} \small Z_{A}=\frac{8}{8}\; \; Z_{B}=\frac{5}{2}$

So formula of compound is $\inline \dpi{100} \small AB_{\frac{5}{2}}$

i.e., $\inline \dpi{100} \small A_{2}B_{5}$

Filed Under: Chemistry
Exam Prep: AIEEE

1 28
Q:

The degree of dissociation ($\inline \alpha$) of a weak electrolyte, $\inline A_{x}B_{y}$ is related to van't Hoff factor (i) by the expression:

$\inline 1.\: \alpha =\frac{x+y+1}{i-1}$

$\inline 2.\: \alpha =\frac{x+y-1}{i-1}$

$\inline 3.\: \alpha =\frac{i-1}{x+y+1}$

$\inline 4.\: \alpha =\frac{i-1}{x+y-1}$

 A) 1 is correct B) 2 is correct C) 3 is correct D) 4 is correct

Explanation:

$\inline \dpi{100} \fn_jvn \small Van't \: \: Hoff \: \: factor (i)=\frac{ Observed \: \: colligative\: \: property}{Normal \: \: colligative \: \: property}$

$\inline \dpi{100} \fn_jvn \small \begin{matrix} A_{x}B_{y}\\ 1-\alpha \end{matrix}\rightarrow \begin{matrix} xA^{+y}\\ x\alpha \end{matrix}+\begin{matrix} yB^{-x}\\ y\alpha \end{matrix}$

Total Moles = $\inline \dpi{100} \fn_jvn \small 1-\alpha +x\alpha +y\alpha$

$\inline \dpi{100} \fn_jvn \small =1-\alpha(x +y-1)$

$\inline \dpi{100} \fn_jvn \small i=\frac{1+\alpha(x +y-1)}{1}$

$\inline \dpi{100} \fn_jvn \small \Rightarrow \alpha =\frac{i-1}{x+y-1}$

Filed Under: Chemistry
Exam Prep: AIEEE

0 10
Q:

Ozonolysis of an organic compound gives formaldehyde as one of the products. This confirms the presence of :

 A) An acetylenic triple bond B) Two ethylenic double bonds C) A vinyl group D) An isopropyl group

Explanation:

$\inline \left.\begin{matrix} C=\\ \end{matrix}\right\}CH_{2}\xrightarrow[]{Ozonolysis} HCHO$

$\inline Vinylic\: \: group$

Filed Under: Chemistry
Exam Prep: AIEEE

0 13
Q:

The structure of $\inline IF_{7}$ is

 A) Pentagonal bipyramid B) Square pyramid C) Trigonal bipyramid D) Octahedral

Explanation:

Hybridisation of iodine is $\inline sp^{3}d^{3}$

So, structure is pentagonal bipyramid.

Filed Under: Chemistry
Exam Prep: AIEEE

0 16
Q:

The outer electron configuration of Gd (Atomic No : 64) is

$\inline 1.\: 4f^{7}5d^{1}6s^{2}$

$\inline 2.\: 4f^{3}5d^{5}6s^{2}$

$\inline 3.\: 4f^{8}5d^{0}6s^{2}$

$\inline 4.\: 4f^{4}5d^{4}6s^{2}$

Sol :$\inline GD=4f^{7}5d^{1}6s^{2}$