Tag: chemistry

Questions Related to chemistry

Which one of these are the simplest pnictogen hydride?

  1. Ammonia

  2. Alkyl amine

  3. Phosphine

  4. Water


Correct Option: A
Explanation:

Ammonia is the simplest pnictogen hydride. N group elements are called pnictogens. And the smallest of all pnictogens is nitogen. So simplest pnictogen hydride is ammonia.

Ammonia is most harmful for:

  1. humans

  2. animals

  3. aquatic organisms

  4. plants


Correct Option: C
Explanation:

The toxicity of ammonia solutions does not usually cause problems for humans and other mammals, as a specific mechanism exists to prevent its build-up in the bloodstream. Ammonia is converted to carbamoyl phosphate by the enzyme carbamoyl phosphate synthetase, and then enters the urea cycle to be either incorporated into amino acids or excreted in the urine. Fish and amphibians lack this mechanism, as they can usually eliminate ammonia from their bodies by direct excretion. Hence ammonia even in dilute solutions is very harmful for aquatic organisms.

Which one of these are the  liquid by-product of the production of coke from coal?

  1. Ammonia

  2. Hydrogen cyanide

  3. Hydrogen fluoride

  4. Hydrogen sulfide


Correct Option: A
Explanation:

Ammonia is the liquid by-product of production of coke from coal.

Neutron's relative charge is :

  1. $-1$

  2. $+1$

  3. $0$

  4. $-2$


Correct Option: C
Explanation:

Neutron is a neutral particle.

In 1932, ___________ discovered an electrically neutral particle in the atom named as neutron.

  1. Rutherford

  2. James chadwick

  3. J.J. Thompson

  4. none of the above


Correct Option: B
Explanation:

in 1932, James Chadwick discovered neutron.

According to J. Chadwick, __________ is not found in hydrogen atom.

  1. neutron

  2. electron

  3. proton

  4. none of the above


Correct Option: A
Explanation:

According to Chadwick, neutron is not not found in hydrogen.

Which of the following statements is false?

  1. Proton has a positive charge

  2. Neutron has no charge

  3. Electrons are found in regions of the atom called orbitals

  4. Electrons has a greater mass than the protons

  5. Protons and neutrons form the nucleons of the atom


Correct Option: D
Explanation:
Electron has less mass. A proton and a neutron have effectively the same mass. A proton (or a neutron) has approximately 1837 times more massive than an electron.

$ _{7}{X}^{15}$ and $ _{8}{Y}^{15}$ differ in

  1. Physical properties

  2. Chemical properties

  3. Number of neutrons

  4. Number of nucleons


Correct Option: C
Explanation:

The option (C) is the correct answer.
$\displaystyle _{7}{X}^{15}$ and $\displaystyle _{8}{Y}^{15}$ differ in number of neutrons.
Number of neutrons for $\displaystyle _{7}{X}^{15} = 15-7=8$
Number of neutrons for $\displaystyle _{8}{Y}^{15}=15*8=7$
Note: Number of neutrons $\displaystyle =$ mass number $\displaystyle -$ atomic number.

Neutrons are present in all atoms except?

  1. He

  2. C

  3. H

  4. Ne


Correct Option: C
Explanation:

The available hydrogen state ${ H } _{ 1 }^{ 1 }$. It is made of 1 electron, 1 proton and no neutrons. All other elements including isotopes of Hydrogen have neutrons.

Number of neutrons present in $1.7$ g of ammonia is:

  1. $0.8N _A$

  2. $0.7N _A$

  3. $0.652N _A$

  4. $0.52N _A$


Correct Option: B
Explanation:
Let us consider the problem.
For, moles of $N{H _3} = \frac{{1.7}}{{17}} = 0.1$
Let the Neutrons in 1 molecules of $N{H _3} = 7 + 3 \times 0 = 7$
Hence,
Number of Neurons $= 0.1 \times {N _A} \times 7$
The correct answer is $0.7{N _A}$