**Core Concept**
Chronic renal failure (CRF) is a complex condition characterized by the progressive loss of renal function, leading to a build-up of waste products and electrolyte imbalances. The kidneys play a vital role in maintaining acid-base balance, regulating blood pressure, and managing electrolyte levels.

**Why the Correct Answer is Right**
Chronic renal failure is often complicated by various secondary effects, including hyperkalemia, acidosis, hypertension, and electrolyte imbalances. The kidneys' inability to filter waste products and excess electrolytes leads to a range of complications. For example, the kidneys' failure to excrete hydrogen ions results in metabolic acidosis, while the retention of potassium ions can cause hyperkalemia.

**Why Each Wrong Option is Incorrect**
**Option A:**
* This option is incorrect because chronic renal failure is indeed often complicated by hyperkalemia, which occurs due to the kidneys' inability to excrete potassium ions.

**Option B:**
* This option is incorrect because chronic renal failure is often complicated by acidosis, which occurs due to the kidneys' failure to excrete hydrogen ions.

**Option C:**
* This option is incorrect because chronic renal failure is often complicated by hypertension, which occurs due to the kidneys' failure to regulate blood pressure and fluid balance.

**Clinical Pearl / High-Yield Fact**
In patients with chronic renal failure, it is essential to monitor electrolyte levels closely, as even small imbalances can have significant consequences. This includes regular checks of potassium, sodium, and calcium levels to prevent complications such as hyperkalemia, hypocalcemia, and cardiac arrhythmias.

**Correct Answer: D.**