25cm\(^3\)
10cm\(^3\)
20cm\(^3\)
50cm\(^3\)
Correct answer is D
Equation of reaction : 2NaOH + H\(_2\)SO\(_4\) → Na\(_2\)SO\(_4\) + 2H\(_2\)O
Concentration of a base, CB = 0.5M
Volume of acid, V\(_A\) = 10cm\(^3\)
Concentration of an acid, C\(_A\) = 1.25M
Volume of base, V\(_B\) = ?
Recall:
\(\frac{C_A V_A}{C_B V_B} = \frac{n_A}{n_B}\) ... (1)
N.B: From the equation,
\(\frac{n_A}{n_B} = \frac{1}{2}\)
From (1)
\(\frac{1.25 \times 10}{0.5 \times V_B} = \frac{1}{2}\)
\(\frac{12.5}{0.5V_B} = \frac{1}{2}\)
25 = 0.5V\(_B\)
VB = 50.0 cm\(^3\)
+5 to +3
+6 to +3
-2 to +3
+7 to +3
Correct answer is B
Cr\(_2\)O\(_7 ^{2-}\) + 6Fe\(^{2+}\) + 14H\(^{+}\) \(\to\) 2Cr\(^{3+}\) + 6Fe\(^{3+}\) + 7H\(_2\)O
The oxidation of Cr in Cr\(_2\)O\(_7 ^{2-}\) :
Let the oxidation of Cr = x;
2x + (-2 x 7) = -2 \(\implies\) 2x - 14 = -2
2x = 12 ; x = +6
Hence, the change in oxidation of Cr = +6 to +3
Which of the following pairs cannot be represented with a chemical formula?
air and bronze
bronze and sodium chloride
copper and sodium chloride
caustic soda and washing soda
Correct answer is A
No explanation has been provided for this answer.
Which of the following describes the chemical property of acids?
None of the above
Acid + XCO\(_3\) \(\to\) Salt + H\(_2\)O + NH\(_3\)
Acid + NaOH \(\to\) Normal salt + CO\(_2\)
Acid + X\(_n\)CO\(_3\) \(\to\) Salt + H\(_2\)O + CO\(_2\)
Correct answer is D
No explanation has been provided for this answer.
Which of the following pollutants will lead to the depletion of ozone layer?
chlorofluorocarbon
carbon (ii) oxide
hydrogen sulphide
sulphur (iv) oxide
Correct answer is A
No explanation has been provided for this answer.