VITEEE 2014 :: Chemistry :: General questions

• Chemistry - General questions

2.76 g  of silver carbonate  on being strongly heated yields a residue weighing

Answer:

Explanation:

Silver carbonate on being strongly heated decomposes as 

$Ag_{2}CO_{3}$ $\underrightarrow{\triangle}$ $2Ag+CO_{2}+\frac{1}{2}O_{2}$

276 g                               216g

 As 276 g of $Ag_{2}CO_{3}$ gives =216g of Ag

 Hence , 2.76 g of $Ag_{2}CO_{3}$ will give 

 $=\frac{2.76 \times 216}{276}=2.16g$

According to Bohr's theory , the angular momentum for an electron of 3rd orbit is 

Answer:

Explanation:

Angular momentum ,mvr

   =$\frac{nh}{2\pi}=\frac{3 \times h}{2\pi}=\frac{1.5 h}{\pi}$

  $=3h$   $[ \because h=\frac{h}{2\pi}]$

A gaseous mixture containing  He,$CH_{4}$ and $SO_{2}$ was allowed to effuse through a fine hole then find what molar ratio of gases coming out initially ?(Given mixture contains $He,CH_{4}$ and  $SO_{2}$ in 1:2:3 mole ratio)

Answer:

Explanation:

$\frac{n'He}{n'CH_{4}}=\frac{1}{2}\sqrt{\frac{16}{4}}=\frac{1}{1}$

$\frac{n'He}{n'SO_{2}}=\frac{1}{3}\sqrt{\frac{64}{4}}=\frac{4}{3}$

So, molar ratio will be 

$n'He:n'CH_{4}:n'SO_{2}=4:4:3$

The bond angles of $NH_{3},NH_{4}^{+}$ and $NH_{2}^{-}$ are in the order

Answer:

Explanation:

On increases the number of lone pairs of electrons , bond angle decreases . therefore , order of bond angle is 

$NH_{4}^{+}$   >$NH_{3}$ >$NH_{2}^{-}$

 (no/p)           (one/p)           (two/p)

In the reaction ,

$8Al+3Fe_{3}O_{4} \rightarrow  4Al_{2}O_{3}+9Fe$ the number of electrons transferred from the reductant to the oxidation is 

Answer:

Explanation:

$8 Al \rightarrow 8Al^{3+}+24e^{-}$

$9Fe^{8/3}+24e^{-} \rightarrow 9 Fe$

 Total 24 electrons are transferred

• Chemistry - General questions