Calculate [h+] for each of the following solutions, and indicate whether the solution is acidic, basic, or neutral.

part a [oh−]= 4.5×10−4 m . express your answer using two significant figures.

part b 1) the solution is acidic 2) the solution is basic 3) the solution is neutral

part c [oh−]= 7.7×10−9 m . express your answer using two significant figures.

part d 1) the solution is acidic 2) the solution is basic 3) the solution is neutral

part e a solution in which [oh−] is 140 times greater than [h+]. express your answer using two significant figures.

part f 1) the solution is acidic 2) the solution is basic 3) the solution is neutral

Part A: 10.7.

Part B: 2) the solution is basic.

Part C: 5.9.

Part D: 1) the solution is acidic.

Part E: 8.1.

Part F: 2) the solution is basic.

Explanation:

Part A [OH−]= 4.5×10−4 M . Express your answer using two significant figures.  

∵ [H₃O⁺][OH⁻] = 10⁻¹⁴.

[OH⁻] = 4.5×10⁻⁴ M.

∴ [H₃O⁺] = 10⁻¹⁴/[OH⁻]  = 10⁻¹⁴/(4.5×10⁻⁴  M) = 2.22 × 10⁻¹¹ M.

∵ pH = - log[H₃O⁺]

∴ pH = - log(2.22 × 10⁻¹¹) = 10.65 ≅ 10.7.

Part B 1) the solution is acidic 2) the solution is basic 3) the solution is neutral  

The solution is basic, because the pH is higher than 7.

Part C [OH⁻]= 7.7×10⁻⁹ M . Express your answer using two significant figures.  

∵ [H₃O⁺][OH⁻] = 10⁻¹⁴.

[OH⁻] = 7.7×10⁻⁹ M.

∴ [H₃O⁺] = 10⁻¹⁴/[OH⁻]  = 10⁻¹⁴/(7.7×10⁻⁹ M) = 1.29 × 10⁻⁶ M.

∵ pH = - log[H₃O⁺]

∴ pH = - log(1.29 × 10⁻⁶) = 5.88 ≅ 5.9.

Part D 1) the solution is acidic 2) the solution is basic 3) the solution is neutral  

The solution is acidic, because the pH is lower than 7.

Part E A solution in which [OH−] is 140 times greater than [H+]. Express your answer using two significant figures.  

∵ [H₃O⁺][OH⁻] = 10⁻¹⁴.

∵  [OH⁻] = 140[H₃O⁺]

∴ [H₃O⁺](140[H₃O⁺]) = 10⁻¹⁴.

∴ 140 [H₃O⁺]² = 10⁻¹⁴.

[H₃O⁺]² = 10⁻¹⁴/ 140 = 7.14 x 10⁻¹⁷.

∴ [H₃O⁺] = √(7.14 x 10⁻¹⁷) = 8.45 x 10⁻⁹ M.

∵ pH = - log[H₃O⁺]

∴ pH = - log(8.45 x 10⁻⁹) = 8.07 ≅ 8.1.

Part F 1) the solution is acidic 2) the solution is basic 3) the solution is neutral

The solution is basic, because the pH is higher than 7.

the correct answer would be d. hope this !