If the pH is 7.60 (H+ concentration = 25 nEq/L) and the pCO₂ is 40 mmHg, what is the HCO₃- concentration (in mEq/liter).

Correct Answer: D

Rationale: Using Henderson-Hasselbalch: pH = 6.1 + log([HCO₃⁻]/(0.03 × pCO₂)), 7.60 = 6.1 + log([HCO₃⁻]/(0.03 × 40)). Solving: 1.5 = log([HCO₃⁻]/1.2), 10^1.5 = [HCO₃⁻]/1.2, 31.6 ≈ [HCO₃⁻]/1.2, [HCO₃⁻] ≈ 40 mEq/L. D (40) matches, indicating alkalosis.

Correct Answer: A

Rationale: Higher GFR (A) increases filtrate volume, reducing PCT reabsorption time, raising Na⁺ concentration reaching the DCT. Decrease (B) or no change (C) assumes full compensation, but faster flow elevates Na⁺, making A correct.

Correct Answer: C

Rationale: ADH increases collecting duct water permeability (C is incorrect), concentrating urine, not decreases it. Osmolarity (A), alcohol (B), and pituitary storage (D) are true, making C the error.

Correct Answer: B

Rationale: Cleaning the catheter before/after use (B) reflects correct home clean technique for intermittent catheterization. Sterile technique (A) is hospital-based, daily new catheters (C) are unnecessary (weekly is fine), and antibiotics (D) aren't routine, making B the effective learning sign.

Correct Answer: C

Rationale: Normally the urinalysis will show zero to trace amounts of protein, but some medications may give false-positive readings. The other actions by the nurse may be appropriate but checking for medications that may affect the dipstick accuracy should be first.