Chemistry Chapter 6 Entry Test MCQs
126. Phenolphthalein is used as an indicator in acid base titration. For which of the following acid base titration it is used as an indicator:
a. Weak acid and weak base
b. Strong base and strong acid
c. Very weak base and strong acid
d. Strong acid and weak base
127. Find the pH of a solution when 0.01 M HCl and 0.1 M NaOH are mixed in equal volumes
a. 7.0
b. 12.65
c. 2.0
d. 1.04
128. Which is correct statement
a. Greater is molar conc. Of H+ greater is pH
b. Conjugate base of weak acid is weak
c. Greater is ka value smaller is pka value
d. Greater is ka value, greater is kb
129. The value of pKw at 25oC is:
a. 14
b. 1014
c. 7
d. 10–14
130. pOH of human blood is:
a. 7.85
b. 7.0
c. 6.65
d. 7.35
131. Which one of the following solutions have zero pH?
a. 0.1 M HNO3
b. 0.5 M HCl
c. 0.5 M CH3COOH
d. 0.5 M H2SO4
132. The value of PH of water at 25oC is 7. The value of PH of water of 100 oC is:
a. ˃7
b. 7
c. 14
d. <7
133. Conjugate acid of very strong base is relatively:
a. Very strong base
b. Very strong acid
c. Very weak base
d. Very weak acid
134. The solution have H+ ion concentration 1/10, its pOH:
a. 1
b. 0
c. 13
d. 14
135. The conjugate acid of NH2– is
a. NH4+
b. NH3
c. N2H4
d. NH2OH
136. Strength of an acid is directly proportional to all except:
a. Ka of acid
b. pH of the acid
c. %age ionization of acid
d. pOH of the acid
137. pH of buffer equals pKa of acid when:
a. Salt comes from weak base
b. Acid is weak
c. Concentration of acid and conjugate acid is same
d. Concentration of salt and acid is same
138. acid with a strong base is
a. Reversible process
b. Non-spontaneous reaction
c. Chemical equilibrium
d. spontaneous reaction
139. Which one of the following is not a buffer?
a. H3PO4 + NaH2PO4 solution
b. H2CO3 + NaHCO3 solution
c. Hl + Nal solution
d. NH4OH + NH4Cl solution
140. pH of the buffer (CH3COOH + CH3 COONa) is 3.76. if the mixture contains 1 molar acetic acid and 0.1 molar sodium acetate, then pKa of this buffer is
a. 4.76
b. 2.76
c. 5.76
d. 3.76
141. Which one of the following is a buffer solution?
a. Glue
b. Brine
c. Solution of CuSO4
d. Blood
142. The decrease in the solubility of an electrolyte by adding another electrolyte having common ion is called common ion effect. Identify incorrect statement about common ions effect:
a. It is always in the reverse direction
b. It is an application of Le-Chatelier’s Principle
c. It is used for the purification of a substance
d. The term electrolyte, acid or base is used for it
Solubility Product
143. The solubility of CaO is S mol dm-3. Its solubility product is equal to
a. 16S4
b. S2
c. S3
d. 4S3
144. The solubility of CaCl2 in water is y moles / dm3. Its solubility product is
a. 36y2
b. 4y3
c. 9y3
d. 108y4
145. All of the following are characteristic features of solubility product EXCEPT?
a. It is applicable if the molar concentration of ions is greater than 0.1M
b. If solubility is known, then Ksp can be calculated
c. The term Ksp is related with reversible process
d. If Ksp is known, then solubility can be calculated
146. If Ksp of Cr2S3 at 25oC is 108S5 then its solubility will be calculated by a formula.
a. ( 108/ksp )1/5
b.
c. ( 108/ksp )1/3
d. ( ksp/108 )1/5
147. AgCl dissociated with concentration 2 x 10-2. Its Ksp will be:
a. 3.6 x 10-6
b. 4 x 10-4
c. 3.6 x 10-5
d. 7.2 x 10-6
148. Which of the following substances has decreasing the solubility by increasing the temperature?
a. KI
b. NH4Cl
c. Li2CO3
d. NaCl
149. The solubility of Ca3(PO4)2 in water is y moles / dm3. Its solubility product is
a. 36y4
b. 6y4
c. 64y5
d. 108y5