Tag: chemistry

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Multiple choice chemistry states of matter: gaseous and liquid states gay lussac's law gas laws states of matter

In the reaction $N _{2}+3H _{2}\rightarrow 2NH _{3} $, the ratio by volume of $N _{2},\ H _{2} :$ and$: NH _{3}$ is $1 : 3 : 2$. 


This illustrates the law of:

  1. definite proportion

  2. multiple proportion

  3. reciprocal proportion

  4. gaseous volumes
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In the reaction, $N _{2}+3H _{2}\rightarrow 2NH _{3} $, the ratio by volume of $N _{2},\ H _{2} $ and $ NH _{3}$ is $1 : 3 : 2$. This illustrates the law of Gaseous volumes or Gay Lussac's law of combining volumes of gases.

According to this law, when gases react together to produce gaseous products, the volume of reactants and products bear a simple whole-number ratio with each other, provided volumes are measured at the same temperature and pressure.

So, the correct option is $D$.

Multiple choice chemistry states of matter: gaseous and liquid states gay lussac's law gas laws states of matter

To use Gay-Lussac's Law, which of the following needs to remain constant?

  1. Volume and the number of moles of a gas

  2. Pressure and temperature

  3. Temperature and the number of moles of a gas

  4. Pressure and the number of moles of a gas

  5. Temperature and volume
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$P \propto T $
At constant volume and number of moles of a gas, the pressure is directly proportional to the absolute temperature.

Hence, option $A$ is correct.

Multiple choice hydrides hydrogen and its compounds hydrogen chemistry

$Ca{H _2}$ is an example of :

  1. Ionic hydride

  2. Covelent hydride

  3. Metallic hydride

  4. Polymeric hydride
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Calcium hydride (CaH2) is formed by an alkaline earth metal and hydrogen, resulting in an ionic bond between the metal cation and the hydride anion.

Multiple choice hydrides hydrogen and its compounds hydrogen chemistry

Which of the following pair behaves strong and weak base hydride :


$NH _3, PH _3, AsH _3, SbH _3, BiH _3$

  1. $NH _3, PH _3$
  2. $NH _3, BiH _3$
  3. $PH _3, BiH _3$
  4. $BiH _3, AsH _3$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In the group 15 hydrides, basicity decreases down the group as the lone pair becomes more diffuse and less available for donation. Thus, NH3 is the strongest base and BiH3 is the weakest.

Multiple choice hydrides hydrogen and its compounds hydrogen chemistry

Ionic hydrides are usually:

  1. good electrical conductors when solid

  2. easily reduced

  3. good reducing agents

  4. liquid at room temperature
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Ionic hydrides are usually good reducing agents. 

$2CO+NaH \rightarrow HCOONa+C$ 
$PbSO _4+2CaH _2 \rightarrow PbS + 2Ca(OH) _2$ 
$Fe _3O _4 + NaH \rightarrow 3Fe +4 NaOH$

Multiple choice hydrides hydrogen and its compounds hydrogen chemistry

The stability of hydrogen halides is in the order of:

  1. $HF>HI>HBr>HCl$
  2. $HI>HBr>HCl>HF$
  3. $HF>HCl>HBr>HI$
  4. $HCl>HBr>HI>HF$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Due to large difference in electronegativity of upper halogens and hydrogen, they are more stable than lower hydrogen halide.
$\therefore $ Stability order: $HF>HCl>HBr>HI$.