The constituent of air necessary in the rusting process are
O2 and H2O
Ar and CO2
CO2 and H2O
O2 and CO2
Correct answer is A
Rust is an iron oxide, a usually red oxide formed by the redox reaction of iron and oxygen in the presence of water or air moisture.
Anhydrous CaCl2
concentrated NaCO4
dilute NaOH
concentrated H2SO4
Correct answer is A
To purify the distillate of impurities like unreacted ethanol, acids, water and ethoxyethane.
Adding anhydrous calcium chloride and leave it to stand for a day to remove any water present
in the mixture.
When element \(_{20}\)Y combines with element \(_8\)Z, it forms
A covalent compound , YZ is formed
A covalent compound, ZY is formed
An ionic compound, YZ is formed
An ionic compound, ZY is formed
Correct answer is C
Y = 2,8,8,2 and Z = 2,6.
Y will readily give off its 2 valence electrons and Z will accept the 2 electrons in order to achieve octet configuration. Hence, the compound YZ is formed by ionic bonding.
How many electrons are present in \(^9_4Be^{2+}\)?
2
4
5
6
Correct answer is A
Neutral Be has 4 electrons but \(Be^{2+}\) means it has lost two electrons from possible four and became a positive ion.
\(\therefore\) the number of electrons left will be equal to two.
136X
137X
196X
197X
Correct answer is A
No explanation has been provided for this answer.