Chemistry - Online Test
Q1. Dihydrogen under certain reaction conditions, combines with almost all elements to form binary compounds, called hydrides except with few which are given below Choose one of the options
Answer : Option D
Explaination / Solution:
Noble gases are inert and have high ionisation enthalpy. Hence, they do not form any hydrides.
Q2. Drugs which mimic the natural messenger by switching on the receptor are called
Answer : Option C
Explaination / Solution:
Agonists are drugs which mimic the natural messenger by switching on receptors.
Q3. What is the coordination number of chromium in [Cr(NH3)2(H2O2)2]Cl3?
Answer : Option D
Explaination / Solution:
There are 4 ligands attachted so CN= 4.
Q4. When measuring conductivity with a conductivity cell, cell constant denoted by the symbol G* is given by (electrode area of cross section equal to ‘A’ and separated by distance ‘l’)
Answer : Option C
Explaination / Solution:
Cell constant = length of electrodes/ Area of electrodes.
Q5. The amount of energy required to break one mole of bonds of a particular type between two atoms in a gaseous state is called
Answer : Option D
Explaination / Solution:
Bond enthalpy, also known as bond energy, is the energy that is needed to break a particular bond in a gaseous compound. The unit that expresses bond enthalpy is kilojoules per mole, or kJ/mol.
Q6. Among the alkali metals the most abundant are:
Answer : Option B
Explaination / Solution:
Na and K are highly abundant. Constituting 2.5 and 2.4 percent of the Earth's crust respectively the othwe alkali metals are considerably rare.
Q7. Which of the following organic compound Wohler synthesised from an inorganic compound, ammonium cyanate in the presence of heat:
Answer : Option B
Explaination / Solution:
The reaction can be given as starting with solutions of potassium cyanate and ammonium chloride which are mixed, heated and cooled again to get ammonium cyanate salt which on decomposition gives the urea.
Q8. According to Gay Lussac’s Law of Gaseous Volumes,
" when gases combine or are produced in a chemical reaction they do so in a ______ ratio by volumes provided all gases are at same temperature and pressure."
Answer : Option A
Explaination / Solution:
Gay lussac’s law states that when gases combine or are produced in a chemical reaction they do so in a simple ratio by volume provided all gases are at same temperature and pressure.
Mathematically , the law is expressed as ,
[ V / n ] = k
where V represents volume of the gas , n denotes number of moles of the gas & k is proportionality constant .
Thus, volume ratio must be related to the relative number of molecules.
This relationship was crucial in establishing the formula of simple molecules at a time when a distinction between atoms and molecules was not clearly understood.
Q9. In the following reaction, the compound used in the reaction for synthesizing ethyl fluoride is – +AgF → H3C – F + AgBr
Answer : Option C
Explaination / Solution:
Alkyl fluorides is only formed by Swartz reaction.in swartz reaction alkyl chlorides or bromide reacts with metallic flouride agf hg2f2 to form alkyl flourides.
Q10. The effect of temperature on reaction rate is given by
Answer : Option C
Explaination / Solution:
k =A exp(-kt)
